trezniti

1. (trezniti se) to sober up
   Još se trezni od sinoćne žurke. — He's still sobering up after last night's party.
   Pio je kafu da se brže trezni. — He drank coffee to sober up faster.
2. (trezniti se, figuratively) to sober up; to come to one's senses
   Posle izbora mnogi birači su počeli da se trezne. — After the elections many voters began to come to their senses.
3. (sb) to sober someone up
   Hladan tuš ga je polako treznio. — The cold shower was slowly sobering him up.
   Takve vesti brzo trezne ljude. — News like that quickly sobers people up.

The perfective is otrezniti (se) or istrezniti (se); otrežnjavati (se) is an imperfective synonym.