The term SUFFIX WITH BUCK can be solved by two four-letter crossword solutions, EROO and AROO. EROO is an informal term for a person who is inexperienced or unskilled at a particular job or activity. AROO is an informal term for a person who is experienced or skilled at a particular job or activity. Both terms are derived from the suffix 'aroo' which is added to the end of a word to indicate a person's level of expertise in a particular field.