drop out

Withdraw from participation in a group such as a school, club, or game; also, withdraw from society owing to disillusionment. For example, He couldn't afford the membership dues and had to drop out, or She planned to drop out from college for a year. [Late 1800s]

Definition: stop doing an activity
Antonyms: begin, carry out, engage, join

1. A variety of power glitch (see glitch); momentary 0 voltage on the electrical mains.

2. Missing characters in typed input due to software malfunction or system saturation (one cause of such behavior under Unix when a bad connection to a modem swamps the processor with spurious character interrupts; see screaming tty).

3. Mental glitches; used as a way of describing those occasions when the mind just seems to shut down for a couple of beats. See glitch, fried.

The verb has 2 meanings:

Meaning #1: give up in the face of defeat of lacking hope; admit defeat
  Synonyms: give up, throw in, throw in the towel, quit, chuck up the sponge
  Antonym: enter (meaning #2)

Meaning #2: leave school or some other program prematurely