ultracrepidariannoun [ C ]
/ˌʌl.trə.krep.ɪˈdeə.ri.ən//ˌʌl.trə.krep.ɪˈder.i.ən/someone who has no special knowledge of a subject but who expresses an opinion about it:
I avoid commenting on football for fear of being called an ultracrepidarian.
ultracrepidarianadjective
uk/ˌʌl.trə.krep.ɪˈdeə.ri.ən//ˌʌl.trə.krep.ɪˈder.i.ən/expressing an opinion about something that you have no special knowledge of:
Her ultracrepidarian husband seems to know everything about everything.