popustiti

1. (+ dat. or pred + instr.) to give in; to yield
   Na kraju je popustio i kupio deci psa. — In the end he gave in and bought the kids a dog.
   Vlada nije popustila pred pritiskom. — The government didn't yield to the pressure.
2. (of pain, weather) to ease off; to subside; to let up
   Bol je popustio posle tablete. — The pain eased off after the pill.
   Kiša je malo popustila. — The rain has let up a little.
3. (of a belt, knot) to loosen
   Popusti malo kaiš. — Loosen your belt a bit.
   Popustio je kravatu i seo. — He loosened his tie and sat down.
4. (of a structure, nerves) to give way; to crack
   Brana je popustila pod pritiskom vode. — The dam gave way under the water pressure.
   Na kraju su mu popustili živci. — In the end his nerves cracked.
5. colloq. (of school, work) to decline in performance; to do less well
   Sin mi je popustio u školi. — My son hasn't been doing as well at school.

The imperfective is popuštati; to give in to someone is popustiti + dat.