overfish Syllabification: (o·ver·fish)Pronunciation: /ˌōvərˈfiSH/Definition of overfish verb [with object] deplete the stock of fish in (a body of water) by too much fishing:this part of the Mediterranean is terribly overfished deplete the stock of (a fish):yellowfin tuna has been overfishedoverfish in other Oxford dictionaries Definition of overfish in the British & World English dictionary