www.etymonline.com has this entry for
ignorance:
c.1374, from O.Fr. ignorant, from L. ignorantia, from ignorantem, prp. of ignorare (see ignore). Colloquial sense of "ill-mannered" first attested 1886. Ignorance is attested c.1225, from O.Fr. ignorance, from L. ignorantia.
I think the "L." means Latin, but I wouldn't know the first thing about conjugation or structure, so how does
"Ignorantem fortitudo est" sound?