This is the 674th most frequent Hungarian word.
tettek
"Tettek" means "deeds" or "actions" in English.
In this sentence, 'tettek' means 'deeds' or 'actions' in the context of things people do.
A jó tettek boldoggá teszik az embereket.
Good deeds make people happy.
Here 'tettek' means 'did' or 'prepared', as it is the past tense of 'tesz', indicating they committed an action.
A tolvajok sötétedés után tettek maguknak némi ennivalót.
The thieves prepared some food for themselves after dark.
'Tettek' here again refers to 'actions', used in a figurative sense to describe impactful past deeds.