The term 'REALLY FUNNY' can be described by the following crossword solutions: UPROARIOUS (10 letters), RIOTOUS (7 letters), RICH (4 letters), AHOOT (5 letters), ASCREAM (7 letters), GUTBUSTING (10 letters), and RIBTICKLING (11 letters). These words all describe something that is extremely humorous, often causing uncontrollable laughter. UPROARIOUS and RIOTOUS both suggest a chaotic atmosphere, while RICH implies that the humor is of a high quality. AHOOT and ASCREAM both suggest loud, uncontrollable laughter, and GUTBUSTING and RIBTICKLING imply that the humor is so strong that it causes physical reactions such as stomach pain from laughing too hard.