Jaw breaker is a type of hard candy that is difficult to bite into. It is also known as a 'gumball' or 'GUMDROP'. The term 'jaw breaker' is derived from the fact that it is so hard that it can break one's jaw if bitten into too hard. The crossword solution for the term 'jaw breaker' is FIST, which is an acronym for 'Firmly Impacted Sugar Treat'. This acronym is used to describe the hard texture of the candy.