The crossword solutions for the term 'THAT'S NOT FAIR!' are BOO (3 letters) and CMON (4 letters). BOO is an expression of disapproval or disappointment, usually used to express disapproval of something unfair. CMON is an abbreviation of 'come on', which is an expression used to encourage someone to do something or to express disbelief or frustration at something that has happened. Both expressions are used to express dissatisfaction with something that is not fair.