The term 'ADHERENT's Suffix' refers to a suffix that is added to the end of a word to indicate a person who adheres to a particular belief or practice. The three crossword solutions for this term are IST (3 letters), ITE (3 letters), and ISTS (4 letters). IST is an abbreviation for 'ist', which is a suffix used to denote a person who believes in or practices a certain doctrine, system, or philosophy. ITE is an abbreviation for 'ite', which is a suffix used to denote a person who follows or adheres to a particular group, movement, or cause. ISTS is an abbreviation for 'ists', which is a plural form of 'ist' and is used to denote multiple people who believe in or practice a certain doctrine, system, or philosophy.