informal Those who find lost things can keep them. Used usually by children to claim the right to keep something they have found. I don't have to give it back; it's finders keepers. Finders keepers, losers weepers! It's my knife now!
FINDERS KEEPERS
Meaning of FINDERS KEEPERS in English
American idioms English vocabulary. Английский словарь американских идиом. 2012