ig·no·rant 
(ĭgnər-ənt)
(ĭgnər-ənt)adj.
1. Lacking education or knowledge.
2. Showing or arising from a lack of education or knowledge: an ignorant mistake.
3. Unaware or uninformed: was ignorant of the drug's harmful effects.
[Middle English ignoraunt, from Old French ignorant, from Latin ignōrāns, ignōrant-, present participle of ignōrāre, to be ignorant, not to know; see gnō- in the Appendix of Indo-European roots.]
igno·rant·ly adv.