Gambits have been a popular part of chess since the romantic era of the game in the 19th century. The word comes from the Italian "gambetto" (tripping), and the concept involves offering material to knock the opponent off balance. Some gambits are considered sound (the compensation is objectively sufficient), while others are considered dubious but practically effective.
The Queen's Gambit (1.d4 d5 2.c4) is the most famous gambit, though it is not a true gambit because Black cannot safely hold the offered pawn. The King's Gambit (1.e4 e5 2.f4) is a true gambit that sacrifices a pawn for open lines and rapid kingside development. Modern gambits like the Marshall Attack in the Ruy López sacrifice a pawn for lasting initiative and attacking chances.
Playing gambits requires confidence and tactical skill, since the compensation must be converted before the opponent consolidates. Defending against gambits requires patience and precision, returning the material at the right moment to neutralize the opponent's initiative while maintaining a structural or material advantage.