creepmouse adjective 1noun 1forms 3 adjective1 •Timid and unassuming in the extreme.A box of manuscripts, buried with Ash by Ellen, his creepmouse widow, is opened; the lovers' final secrets are revealed. Ellen, we find, had never let Ash consummate their marriage. — 1990 noun1 •An extremely timid and unassuming person.Don't be such a frightened little creepmouse. I take a deep breath, look at the feet again, and giggle. — 2009 formscreepmice · more creepmouse · most creepmouse