Spring on is a phrasal verb that means to surprise or present an unexpected situation to someone. The antonyms for "spring on" are to inform, to warn, or to expect. By informing someone beforehand or giving them a heads up, they will not be caught off guard or surprised by the situation. Therefore, by providing a warning, one can anticipate the situation and prepare themselves adequately. Conversely, when we expect something to happen, we prepare ourselves mentally and emotionally for it, and we do not get flustered or overwhelmed. In essence, antonyms for "spring on" have to do with providing foreknowledge so that one can better handle the situation or respond accordingly.