overthink Syllabification: (o·ver·think)Pronunciation: /ˌōvərˈTHiNGk/Definition of overthink verb [with object] think about (something) too much or for too long:must you overthink every relationship? [no object]:he doesn’t make snap decisions, but he doesn’t overthink eitheroverthink in other Oxford dictionaries Definition of overthink in the British & World English dictionary