unfamiliar /ˌʌnfəˈmɪli.ə(ɹ)/adjective 1noun 1forms 3 adjective1 •Strange, not familiar.United were second-best for long periods as they struggled to adapt to an unfamiliar line-up and were ultimately fortunate to leave Merseyside with their unbeaten league run still intact. — 2011 noun1 •An unfamiliar person; a stranger. formsunfamiliars · more unfamiliar · most unfamiliar