thief Look up thief at Dictionary.com
O.E. þeof, from P.Gmc. *theubaz (cf. O.Fris. thiaf, O.S. thiof, M.Du. dief, O.H.G. diob, Ger. dieb, O.N. þiofr, Goth. þiufs), probably from PIE *teup- (cf. Lith. tupeti "to crouch down").