The term 'HAPPY MOLLUSK' is composed of two words, 'HAPPY' and 'MOLLUSK'. The first word, 'HAPPY', is a four-letter word meaning feeling or showing pleasure or contentment. The second word, 'MOLLUSK', is a type of invertebrate animal that has a soft body and lives in the sea. The crossword solution for this term is 'CLAM', which is a type of MOLLUSK that has two shells and lives in the ocean. Clams are known to be a source of food and are often used in recipes.