unsure

Adjective

• Not certain or confident; doubtful.
• lacking self-confidence
  • "a very unsure young man"
• lacking or indicating lack of confidence or assurance
  • "unsure of himself and his future"
  • "moving with uncertain (or unsure) steps"

Adj

• uncertain, ambivalent.
• unstable or precarious

Examples

• I was unsure if ’QI’ was still a valid word in Words With Friends, so I checked the dictionary.
• I'm still unsure whether to attend the wedding.

Synonyms

diffident, incertain, shy, timid, uncertain, agnostic

Antonyms

certain, confident, sure