drop out

Short definition from Wiktionary

Verb

1. 1
   To leave (school, a race, etc.) prematurely and voluntarily.
2. 2
   To opt out of conventional society.
3. 3
   To be lost or momentarily interrupted.
4. 4
   Used other than figuratively or idiomatically: see drop, out.
5. 5
   To give way under someone.
6. 6
   To cause someone to slip and/or fall down.
7. 7
   To dismiss, break up with or abandon (someone).

Noun

1. 1
   Alternative spelling of dropout.