cocksure

/ˈkɑkˈʃʊr/
adjective
  1. Overconfident or arrogantly certain, often without good reason.
    • Being cocksure can make you ignore important warnings from others.
    • She spoke with a cocksure tone that annoyed her colleagues.
    • The young intern was cocksure about his plan, but it failed completely.
Antonyms
What does "cocksure" mean? | whatsthatwordmean | whatsthatwordmean