A pick up line is any one-line
attempt at an ice-breaker
with somebody of the sex
that the speaker is attracted to. The idea is to impress the other person to such a degree that they immediately become enamored
with you or want you or will settle for you.
I disagree that the goal of a pick up line always is to get a person to have sex with you. Yet I must concede that it is usually the goal. Because of this the art of delivering a witty or funny ice-breaker is now looked down upon. Most these days are rude and crude, and the ones that aren't are seen as cheesy and cliché. Most women are turned off by any form of a pick up line. Just introduce yourself and then use your wit and charm in conversation (this is unfortunately the part I have problems with).