doubt

noun1 of 2

not being sure of something; lack of certainty

• “He is, without a doubt, a really talented young man.”Tatoeba
• “I very much doubt that that will make any difference.”Tatoeba

Sentences from Tatoeba show real usage. A word can have several meanings, so a sentence may use another one.

verb2 of 2

To be undecided about; to lack confidence in; to disbelieve, to question.