As a noun: the
act of staying awake
long into the
night, well beyond the hours one's body is adapted to.
As a verb: to undertake such an action.
(From sleep deprivation; see also self-deprecation, depression)
"
Wow, why's
Mary look so out of it?"
"Oh, Mary depped all night
studying for her biology final. Also, she's a crack addict."