1) the movable stick or trigger of a trap, a trap stick

a) a trap, snare

b) any impediment placed in the way and causing one to stumble or fall, (a stumbling block, occasion of stumbling) i.e. a rock which is a cause of stumbling

c) fig. applied to Jesus Christ, whose person and career were so contrary to the expectations of the Jews concerning the Messiah, that they rejected him and by their obstinacy made shipwreck of their salvation

2) any person or thing by which one is (entrapped) drawn into error or sin