"Not hardly" is a commonly used phrase in colloquial English to describe something that is unlikely to happen. There are several synonyms for this phrase that can be used interchangeably depending on the context. "Barely," "scarcely," and "hardly" are all synonyms that can be used to describe something that is unlikely to happen. Other synonyms include "rarely," "seldom," and "infrequently." These synonyms are often used to convey a sense of doubt or uncertainty about the likelihood of something happening. It is important to remember that context is key when selecting the appropriate synonym for "not hardly".