sandbagger

One who uses a sand-bag; especially, a robber who uses a sand-bag to stun his victims.

A sailing boat that uses sand-bags as ballast.

An assaulter whose weapon is a sand bag. See Sand bag, under sand.

One who sandbags (misleads about his/her ability level in order to win bets); a hustler.

someone who deceives you about his true nature or intent in order to take advantage of you