faff about – To waste time on an unproductive activity [wiktionary][urbandict]

Designing a new product is all about balancing trade-offs – how to get the best out of the limited budget. Someone propoosed to add a feature to the product, but was objected by another: “It looks nice but is not essential. I don’t think it is worth one month time faffing about how to implment it.” This phrase is mainly used in the British English (according to wiki). So if you say it to an American, you may get a puzzled look.

love handles – excess fat around the waistline (often used in the plural) [dict]

I wonder why they are called “love handles“, maybe because they provide a soft place to rest one’s hand while one’s arm is around a person. Just maybe, don’t take it too seriously. It helps memorize.

One synonym is “spare tire”, whose meaning is intuitive though less vivid.

big cheese – a very important or influential person [dict]

A colleague passed me a paper and asked me: “do you know the second author of this paper?” He continued: “You should know him. He is a professor in Oxford, a big cheese in the field.”

knocked up — pregnant [dict]

On the latest issue of Reader’s Digest, a woman tells a story from her experience — once during rush hour, she was accompanying her very pregnant colleague to cross the street. They dodged cars and ignored the hooting. Then they heard a furious driver shouting: “Hey! You can get knocked down too, you know!”

tab tap that ass — a vulgar slang for sex [urbandict].

One night, people in our research group went out to celebrate for someone passing the PhD viva. In the pub, an American guy wanted to make fun of a British chap, who seemed to really hit it off with a girl he just met. The American sent him a text message: “Tab Tap that“. After taking a mouthful of beer, he said to me: “I bet he won’t understand. He is British.” I heard this phrase on some American movies before.

son of a gun — a rascal; a scamp [answers]

On ‘Frasier’, Frasier meets Roz’s family, pretending to be her boyfriend, Roger. The family are delighted to meet “Roger” finally. One of Roz’s relatives greets Frasier: “Hey you, son of a gun.” In some dictionaries, the phrase “son of a gun” is defined as a euphemism for “son of a bitch” (see here). So don’t over use it

have no beef with someone — have no quarrel with. “Beef” here has the meaning of “complaint” [answers]

On ‘Rambo: First Blood II’, Rambo found himself in a one man war against the whole police force of a town. From a hill, he jumped upon an army truck and took the driver by surprise.  Just before being kicked out of the truck, the poor diver begged: “Please don’t do that. I have got no beef with you.”

make a pass at someone — to act toward someone in a way that shows a sexual interest in them [thefreedict]

On “When Harry met Sally”, Sally recalled the day when she first met Harry: “He tried to make a pass at me, and when I said no, he was going with a girlfriend of mine”.

hop up — to excite; make enthusiastic [dict]

On a TV show, a group of friends are rehearsing a play. One guy is apparently excited to get a role. However, he doesn’t follow the script. Instead, he improvises his lines, imitates others’ speaking and makes funny noise. When his friends give him an angry look, he excuses himself: “Sorry, I am hopped up.”

wuss — A person regarded as weak or timid and especially as unmanly [dict]

If a guy acts like a baby or a girl, one may say to him: “Don’t be such a wuss (or be wussy)”. This phrase seems common in daily conversations.

click — to function well together; hit it off [dict]

On ‘Monk’, Monk has a lot of phobias, and generally is not easygoing with people. He changed three working partners in two weeks. “We really didn’t click,” he explained.

suck it up — get up and do it, be strong, do not be a quitter [westhost][dict]

On ‘Monk’, Monk and Sharona are visiting a circus for a crime investigation. However, it turns out that Sharona has an awestruck feeling about elephants, which is rooted to a traumatic experience in her childhood. Monk is amused and lectures her: “Come on, suck it up!” However, this really pisses Sharona off, since Monk himself has a lot of phobias, like fearing dust, milk, height, and to shake hands with strangers.

loaded — very rich [urban]

On ‘CSI’, the officers asked a student some questions about his roommate. The student said: “This guy is generous. His Dad is loaded.”

cash cow — A steady dependable source of funds or income [dict]

In Chinese, we have a phrase "money-dropping tree" — the tree grows full of money and one simply shakes it to reap endlessly. I found the English equivalent on 'Desperate Housewives'. "I am a professional model," Gabrielle said proudly, "My face is a cash cow."

wacky — Crazy; silly [dict]

Yesterday afternoon, I attended a very entertaining seminar on compromising locks by bumping. The invited speaker demonstrated an easy way of opening a lock with a gentle whack. It was a very impressive talk. The general principle behind is Newton's third law of motion — simply put, when you hit something, you get a rebound. It's easy to find a key which can be inserted into the keyhole of a target lock. A gentle turn of the key applies a torque force to suppress the movements of the bottom pins inside the lock. Then, a mere whack on the the lock surface rebounds the upper pins and achieves the "Holy Grail" in lock-picking — the upper pins are aligned in the sheer line. Given a few trials to get the timing right, one can open the lock in less than 5 seconds. The audience were overwhelmed. One asked, "I once heard a wacky story that someone injects the compressed air into the keyhole to open the lock." The speaker smiled and said, "Why bother if things can be done in a simpler way." This is a real threat, and people should at least be aware of this problem. Welcome to the world of insecurity!

two-time — To be unfaithful to [dict]

In Desperate Housewives, when Susan was in hospital, waiting for the operation, a young doctor fell in love with her. A nurse, who had a crush on the doctor, felt jealous. When she discovered that Susan was still married, she angrily questioned Susan why she cheated the doctor. Susan tried hard to explain that the reason she didn’t tell the doctor was to protect him. Finally, the nurse believed her and said, “OK, as along as you are not two-timing him.”

goody-two-shoes (goody-goody) — One who is always good and virtuous [dict] [origin]

(From the discussion in ukcrypto)

— “OK, truth time: hands up those who never practiced a parent’s signature for some nefarious purpose (often school linked)?”
— “At the risk of sounding like a goody-two-shoes, I can say I never did.”

booty call — a vulgar slang for having sex, see [urban]

In “Two and a Half Man”, Alan hooked up with a 22-year old over-exuberant girl. One day, when Alan was having meal with his 8-year old son Jake, his girlfriend rang the door bell and shouted, “Alan, I come to surprise you with the booty call.” Jake turned to his uncle, Charlie, for the meaning. Charlie made a face and said why not ask your father; so did Jake. Alan, in front of his girlfriend, made a great effort to sugarcoat this phrase, by telling Jake stories about old-time cowboys. Finally, his girlfriend was amused, and said, “You make it fun. But since when did it not mean casual sex.”

pump up — do body-building [dict]

In “CSI”, a plastic card was found in the pocket of a burned body. A guy quickly recognized that it was a gym membership card, as he had one too. His colleague was amused and asked him, “When did you start pumping up?”

dingus — another word for a spaz [dict]

In Friends, Phoebe asked a guy why he was always following her. It turned out that guy, named Malcolm, mixed up Phoebe with her twin sister. “I am stalking the wrong woman,” he blamed himself, “I am such a dingus!”

going postal — be extremely angry, in an outburst of violence [dict] [wiki]

I countered encountered this “going postal” in Schneier’s blog. A bit research on it reveals the gruesome origin of this phrase. On 20 August, 1986, in Edmond, Oklahoma, a postman shot dead fourteen of his colleagues and wounded six. This mass-killing event gave rise to the term “going postal“. (History repeated itself a few days ago, see news). For the past 20 years, this slang has been used with dark humor. An example usage is this — “The next time Jerry Rice goes four quarters without a touchdown, some NFL cornerback is sure to explain that he ‘defensed him pretty good.’ It’s enough to make a grammar purist go postal.”

hook up — to 1) meet, or 2) be sexually involved with [dict]

Native English speakers often use “I will hook up with you later” to mean “I will meet you later”. However, from the dictionary, this phrase also has “that” connotation. Would it be embarrassing if it is wrongly used as in the case of “be intimate with“? I asked a native speaker this question. He clarified that unlike the phrase “be intimate with”, the meaning of “hook up” largely depends on the context and is usually clear — e.g., if you say ‘let’s hook up after the lecture and discuss your plan’, there is no room for misinterpretation. “But if you are in a pub, sitting next to a hot girl you just met, and say ‘let’s hook up after the drink’, it will be interpreted differently”, he explained with a grin.

dead meat — death [dict]

Chinese friends sometimes kid each other by threatening: “if you dare to go against me, you are sure to die.” The native English expression is “you are dead meat“. The word “meat” makes the sentence a bit funny.

put out — to make efforts. The meaning in the example below is: to be sextually active [dict]. (also see comments)

Phoebe went on a date with a guy she really liked. She made efforts to impress him, but the guy stayed indifferent to this relationship. After the date, Joey asked Phebe: “The guy still won’t put out, huh?”