furtive (adj.)

16c., from Middle French furtif (16c.), from Latin furtivus "stolen," hence also "hidden, secret," from furtum "theft, robbery; a stolen thing," from fur (genitive furis) "a thief, extortioner," also a general term of abuse, "rascal, rogue," probably from PIE *bhor-, from root *bher- (1) "to carry; to bear children." Related: Furtiveness.