(Adjective) to be dishonest or a general jerk; originally derived from the character Captain Hook; to be two-faced

When you hook up with an ugly guy to make a hott guy jealous. Generally done when drunk, it seems like a good idea at the time but the next morning you'll regret it.

Also referred to as simply Meredith.

In reference to Grey's Anatomy; refers to the act of connecting sexually or romantically with a close friend (often who has sexual/romantic feelings towards you) which you have no sexual or romantic feelings towards. Often occurs due to loneliness/horniness or confusion.
This act will usually be followed by an immediate negative reaction from the "Meredith", after realising that they have made a mistake.

to hook up with a girl and lead her on and then tell her that you "dont want a relationship"

The act of suddenly grabbing a good-looking person with a "hook" move on the dance floor and pulling this person to you while your friends quickly take a picture in the hope of improving your own Facebook status.

An expression used when a man is fortunate enough to hook-up with a mother and daughter right after each other. This usually occurs when both parties are inebriated.

The act of going in to hook up with a girl without asking or planning on it. This is usually done at the most oddest of times, and also is very very random. This lasts for about one minute.