eyewitness /ˈaɪˌwɪt.nəs/noun 1verb 1forms 3 noun1 •Someone who sees an event and can report or testify about it.And the girl's fate he could picture as plainly as though he were an eyewitness to it. — 1915 verb1 •To be present at an event or incident, and see and observe it. formseyewitnessed · eyewitnessing · eyewitnesses