BridgeHands

Sandbagger - Referring to a player making an irregular bid.
 

1.

A player holding significant values that initially passes, allowing the opposition to dominate the auction.  Later before the final pass, the sandbagger either throws in a bid hoping opponents will make a poor double, or the sandbagger will make a double knowing the opponents have overbid based on the honors, tenaces, or poor trump suit distribution.

2.

A derogatory colloquial term perceiving a player deliberately (and unlawfully) changed their tempo during bidding or play (usually a hesitation).  The belief is that the sandbagger made an attempt to seduce the opposition into believing the sandbagger holds cards based on their timing.  The Sandbagger's motivation may be to make a subsequent penalty double, or to make a belated make an achievable bid that opponents would unknowingly double.  Another unlawful sandbag is to hesitate or make other noticeable gestures to provide the appearance the sandbagger holds finessable cards under dummy.  See Cheating