(idiomatic) To begin an activity immediately and with full commitment.

(advertising) The first spot in a print advertisement noticed by the reader.

(idiomatic, transitive) To reveal or prove (something) to be false; to refute.

(boxing) Of a punch, landing illegally, below the opponent's waist. / (by extension, idiomatic) Unfair; dirty; not according to the generally accepted rules.

(idiomatic) To cause a specific vehicle to accelerate; to open the throttle of an engine.

(mathematics) The problem, proposed by ancient Greek geometers, of using a finite ruler-and-compass construction to make a square with the same area as a given circle.

(idiomatic) A guess, attempt, or choice made with little or no evidence or knowledge.

(idiomatic) To deal with a matter in a direct manner, especially to confront a difficulty rather than avoid it.

(poker) To raise the stakes of a hand of poker / (dispute) To take an action that raises the stakes, i.e. that increases the chances of conflict. / (idiomatic) To make something more difficult.

(idiomatic) To understand, at least on some basic or general level.