stumbling block

from προσκόπτω; a stub, i.e. (figuratively) occasion of apostasy:--offence, stumbling(-block, (-stone)).

("scandal"); probably from a derivative of κάμπτω; a trap-stick (bent sapling), i.e. snare (figuratively, cause of displeasure or sin):--occasion to fall (of stumbling), offence, thing that offends, stumblingblock.