dif ‧ fi ‧ dent /ˈdɪfəd ə nt, ˈdɪfɪd ə nt/ BrE AmE adjective
[ Date: 1400-1500 ; Language: Latin ; Origin: present participle of diffidere 'to distrust' , from fidere 'to trust' ]
shy and not wanting to make people notice you or talk about you
diffident manner/smile/voice etc
diffident about
He was diffident about his own success.
—diffidently adverb
—diffidence noun [uncountable]