The crossword solution for the term 'Makes a Big Mistake' is 'SINS'. This is a reference to the religious concept of sin, which is defined as an action that goes against the teachings of a religion or moral code. In Christianity, sin is seen as an offense against God and is believed to be punishable by divine retribution. In other religions, sin is seen as an act that goes against the natural order of things and can lead to negative consequences.