b. To force by crude means; coerce: sandbagged us into cleaning up their mess.
c. To downplay or misrepresent one's ability in a game or activity in order to deceive (someone), especially in gambling: sandbagged the pool player by playing poorly in the first game when stakes were low.
verb, intransitive Slang
To downplay or misrepresent one's ability in order to deceive someone, especially in gambling.