/ig'neuh ray"meuhs, -ram"euhs/ , n. , pl. ignoramuses .
an extremely ignorant person.
[ 1570-80; ignoramus we ignore (1st pers. pl. pres. indic. of ignorare to be ignorant of, IGNORE); hence name of an ignorant lawyer in the play Ignoramus (1615) by the English playwright G. Ruggle, whence current sense ]
Syn . simpleton, fool, dunce, know-nothing.