Definition of "Sandbag" :

noun: a bag filled with sand; used as a weapon or to build walls or as ballast

verb: protect or strengthen with sandbags; stop up

"The residents sandbagged the beach front."

verb: downplay one's ability (towards others) in a game in order to deceive, as in gambling

verb: hit something or somebody as if with a sandbag

verb: compel by coercion, threats, or crude means

"They sandbagged him to make dinner for everyone."

verb: treat harshly or unfairly