1. A deal when all four players pass – the term comes from rubber bridge where players would literally throw in their cards for a redeal.
2. To give a player the lead deliberately, with the expectation of a favourable return.
Here is an example:
South plays in 6♥. West leads the ♦K. Declarer wins this, draws trumps, cashes three rounds of spades and leads the ♦J. This throws West in. West has the lead but does not want it: a club goes into the tenace while any pointed suit card would give a ruff and discard.