(intransitive) to boil, to come to the state of vaporizing / (intransitive) to boil, to be cooked, to stew / (intransitive) to become welded, knit. / (intransitive) to swarm, to teem, to abound

(intransitive, idiomatic) To be excited, lively and energetic. / (intransitive, idiomatic, with dative) To feel an affection towards someone shortly after meeting them, to hit it off.