Familiar  —adj. 1 a (often foll. By to) well known. B often met (with). 2 (foll. By with) knowing a thing well. 3 (often foll. By with) well acquainted (with a person). 4 informal, esp. Presumptuously so. —n. 1 close friend. 2 (in full familiar spirit) supposed attendant of a witch etc.  familiarity n. Familiarly adv. [latin: related to *family]