Synonyms for Unacquainted (same or very similar meaning)
WordNet sense 1 (not knowledgeable about something specified):
innocentWordNet sense 2 (not informed; lacking in knowledge or information):
uninformedWordNet sense 3 (having little or no knowledge of):
unacquainted with, unfamiliar withWordNet sense 4 (not known or well known):
unfamiliarFrom the ODE community, based on WordNetadd/edit