noun

• (figurative) Hiding the full strength, skill, or difficulty of something or someone early in an engagement, in order to gain an advantage.
  "We've seen such games as Sandbagging (managers knowingly lowball sales forecasts as a negotiating ploy) spread with surprising speed, because when the game appears to “work” for one manager, others follow suit[…]"
• (law, M&A) The act of bringing a claim for breach of a covenant or misrepresentation even though the person bringing the claim knew about the issue before closing the transaction and did it anyway.
  "“Sandbagging” in the M&A legal context refers to the right of the buyer to seek indemnification for a breach of a seller’s reps and warranties even though the buyer had knowledge of the misrepresentation on which it is basing its claim prior to the closing date. U.S. case law on sandbagging varies widely across jurisdictions and is subject to change over time."
• (restaurant kitchen jargon) Serving premade food, such as precooked appetizers that need only reheating.