The negative ouble is a form of take-out double in bridge. It is made by responder after his right-hand opponent overcalls on the first round of bidding, and is used to show both support for the unbid suits as well as some values. It is treated as forcing, but not unconditionally so. In practice, the negative double is sometimes used as a sort of catch-all, made when no other call properly describes responder's hand. Therefore, a partnership might even treat the negative double as a wide ranging call that merely shows some values.