cocksure

UK: /ˌkɒkˈʃʊə^r/, /ˌkɒkˈʃɔː/

US: /ˈkɑkˈʃʊr/

US: (kok′shŏŏr′, -shûr′)

WordReference Random House Learner's Dictionary of American English © 2025

cock•sure /ˈkɑkˈʃʊr/   adj. 

1. overly sure;
   overconfident:
   a cocksure manner.

cock•sure•ly, adv. 
cock•sure•ness, n. [uncountable]

WordReference Random House Unabridged Dictionary of American English © 2025

cock•sure  (kok′shŏŏr′, -shûr′), adj. 

1. perfectly sure or certain;
   completely confident in one's own mind:
   She was cocksure that she was able to do the job better than anyone else.
2. too certain;
   overconfident:
   He was so cocksure he would win the election that he didn't even bother to campaign.
3. [Obs.] perfectly secure or safe.

• cock¹ + sure 1510–20

cock′sure′ly, adv. 
cock′sure′ness, n. 
Synonyms

• 1. . cocky, arrogant, conceited.

Collins Concise English Dictionary © HarperCollins Publishers::

cocksure / ˌkɒkˈʃʊə -ˈʃɔː/ adjective

1. overconfident; arrogant

Etymology: 16th Century: of uncertain origin

ˌcockˈsureness noun