knav·ish \-vish, -vēsh\adjective Etymology: Middle English knavyssh, from knave + -yssh, -ish -ish : having the characteristics of or appropriate to a knave: a.obsolete: mischievous, roguish < a knavish lad, thus to make poor females mad — Shakespeare > b.: dishonest, fraudulent < knavish booksellers put forth volumes of trash — T.B.Macaulay >