usage: someone who withdraws from a social group or environment
Verb
1. drop out, give up, fall by the wayside, drop by the wayside, throw in, throw in the towel, quit, chuck up the sponge
usage: give up in the face of defeat of lacking hope; admit defeat; "In the second round, the challenger gave up"
2. drop out, retire, withdraw
usage: withdraw from established society, especially because of disillusion with conventional values; "She hasn't heard from her brother in years--he dropped out after moving to California"
3. drop out, leave, depart, pull up stakes
usage: leave school or an educational program prematurely; "Many students drop out because they are not prepared for our challenging program"