jerk off

Short definition from Wiktionary

Verb

1. 1
   To masturbate by manually stimulating one's own penis.
2. 2
   To manually stimulate someone else's penis; to give a hand job.
3. 3
   To do nothing; to waste time.
4. 4
   To deceive.
5. 5
   Used other than figuratively or idiomatically: see jerk, off.

Noun

1. 1
   Alternative form of jerkoff (“an obnoxious person”).
2. 2
   An act of masturbation.
3. 3
   A stunt in which the performer is suddenly pulled off a horse, etc. by means of a cable.
4. 4
   Alternative spelling of jerkoff.