lomiti

1. to break
   Deca stalno lome grane u parku. — The kids keep breaking branches in the park.
   Za Božić se česnica lomi rukama. — At Christmas the česnica bread is broken by hand.
2. (lomiti se) to break; to crack
   Led se lomi pod nogama, vrati se! — The ice is cracking underfoot, come back!
3. (lomiti se, of a decision) to be torn; to agonize
   Danima sam se lomio da li da prihvatim posao. — I agonized for days over whether to take the job.
4. colloq. (impersonal, of the body) to make someone ache all over
   Sve me nešto lomi, mislim da imam grip. — I'm aching all over, I think I have the flu.
5. (of resistance, will) to break someone's resistance or spirit
   Dugi pregovori polako lome njegov otpor. — The long negotiations are slowly breaking his resistance.
6. (lomiti se, of light, rays) to be refracted
   Svetlost se lomi kada prelazi iz vazduha u vodu. — Light is refracted when it passes from air into water.

The perfective is slomiti (to break, to break resistance); for lomiti se "to break (intr.)" it is slomiti se. The verb prelomiti means "to finally make up one's mind" after hesitating (lomiti se), but it is not its aspect partner. Of light, people in Serbia usually say prelamati se (prelamanje svetlosti).