The phrase "anted up" refers to contributing a certain amount of money or resources to a particular cause or effort. Antonyms for "anted up" would be words or phrases that express the opposite meaning, such as "refused to contribute," "withdrew support," or "declined to participate." These antonyms convey a sense of non-commitment or non-involvement, rather than active participation. Other possible antonyms for "anted up" might include "abstained," "stood down," or "opted out," all of which suggest a lack of willingness to contribute or support a particular cause or undertaking.