The term 'REALLY BIG SHOW' can be broken down into four crossword solutions: EPIC (4 letters), SMASH (5 letters), EXTRAVAGANZA (12 letters), and EXPO (4 letters). EPIC is an adjective meaning impressive or grand in scale or character. SMASH is a verb meaning to break something into pieces with great force. EXTRAVAGANZA is a noun meaning a spectacular or extravagant show. EXPO is a shortened form of the word exhibition, which is a large public display of items or activities. Together, these words describe a large, impressive, extravagant show that is sure to be a smashing success.