dropout

noun

1. (countable, uncountable)Someone who has left an educational institution without completing the course

   “The politicians of the world are mere political university dropouts.”

2. (countable, uncountable)Someone who has opted out of conventional society.
3. (countable, uncountable)One who suddenly leaves anything, or the act of doing so.

   “The pastures are filled with gay political drop-outs, persons of reasonable intent who found the scene personally destructive.”

   “To avoid excessive dropouts from the study, we wouldn't employ a single tutored group and a single control group that received no instruction at all.”

4. (countable, uncountable)The slot in the frame that accepts the axles of the wheels.
5. (countable, uncountable)A damaged portion of a tape or disk, causing a brief omission of audio, video, or data.
6. (countable, uncountable)Momentary loss of an electronic signal.
7. (countable, uncountable)A technique for regularizing a neural network by discarding a random subset of its units.