The phrase "as like as not" is an idiom that means something is very likely to occur. It's a phrase that can be used in both formal and informal situations. There are several synonyms for this phrase that can be used interchangeably in different contexts. Some of the common synonyms include 'probably,' 'likely,' 'possibly,' 'in all likelihood,' 'nearly certain,' 'very probable,' 'most likely,' 'presumably,' 'almost certainly,' and 'apparently.' These synonyms express the same level of probability or likelihood as the original phrase and can be used to convey the same meaning in a more succinct or expressive manner.