The term 'Fair or 'FOUL'' is a phrase used to describe a situation in which one must decide whether something is right or wrong. The four-letter answer to this crossword puzzle is 'CALL, ' which can refer to a number of different things, such as a phone CALL, a decision made by an official in a sporting event, or a demand for justice. In this context, it could be interpreted as a CALL to make a judgement on the morality of a situation.