cocky

ˈkɒki

adjective

conceited or confident in a bold or cheeky way.

we were young, brash, cocky—we knew everything

arrogant,conceited,overconfident,overweening,cocksure,smug,haughty,supercilious,disdainful,lofty,patronizing,proud,vain,vainglorious,self-important,swollen-headed,egotistical,presumptuous,lordly,pompous,blustering,boastful,brash,self-assertive,opinionated,bold,forward,insolent,high and mighty,throwing one’s weight about,throwing one’s weight around,uppish,hubristic