doubtdoubtdoubtsdoubteddoubting2verb (doubts, doubting, doubted)to not feel sure about something; to think that something is probably not true or probably will not happen: I doubt if he will come.doubtdoubtdoubtsdoubteddoubting1nounpronunciationThe word doubt sounds like out, because we don't say the letter b in this word.a feeling that you are not sure about something: She says the story is true but I have my doubts about it.in doubtnot sure: If you are in doubt, ask your teacher.no doubtI am sure: Paul isn't here yet, but no doubt he will come later.