all-or-nothing adjective2 •Being or relating to a situation where a dichotomy (a binary state) pertains: either of two poles is instantiated, with no intermediate state (e.g., a mixture or syncretism) being possible or being permitted. •Being or relating to a project that will either succeed completely or fail completely.A crewed moonshot is an all-or-nothing affair: either they get to the moon and back alive, or they don't.