a bag filled with sand, used in fortification, as ballast, etc.

such a bag used as a weapon.

to furnish with sandbags.

to hit or stun with a sandbag.

Informal .

to set upon violently; attack from or as if from ambush.

to coerce or intimidate, as by threats

The election committee was sandbagged into nominating the officers for a second term.

to thwart or cause to fail or be rejected, esp. surreptitiously or without warning

He sandbagged our proposal by snide remarks to the boss.

Poker . to deceive (one or more opponents) into remaining in the pot by refraining from betting on a strong hand, then raising the bet in a later round.

Poker . to sandbag one or more opponents.