We found 11 dictionaries that define the word happy as a clam:

General (6 matching dictionaries)

1. (as) happy as a clam, happy as a clam: Merriam-Webster
2. happy as a clam: Oxford Learner's Dictionaries
3. happy as a clam: Wiktionary
4. Clam, Happy as a: The Word Detective
5. happy as a clam: TheFreeDictionary.com
6. Happy as a clam: World Wide Words

Business (1 matching dictionary)

7. happy as a clam: Legal dictionary

Computing (1 matching dictionary)

8. happy as a clam: Encyclopedia

Medicine (1 matching dictionary)

9. happy as a clam: Medical dictionary

Miscellaneous (1 matching dictionary)

10. happy as a clam: Idioms

Slang (1 matching dictionary)

11. happy as a clam: Urban Dictionary

Definitions from Wiktionary (happy as a clam) ▸ adjective:  (simile) Very happy and carefree. Similar: happy as a clam at high water, happy as a jaybird, happy as a lark, happy as a possum up a gum tree, happy as a sandboy, happy as a prince, blithesome, contented, comfortable, blitheful, more... Opposite: unhappy, sad, depressed, discontented, unfulfilled Phrases: as happy as a clam, more... ▸ Words similar to happy as a clam ▸ Usage examples for happy as a clam ▸ Idioms related to happy as a clam ▸ Wikipedia articles (New!) ▸ Popular nouns described by happy as a clam ▸ Words that often appear near happy as a clam ▸ Rhymes of happy as a clam ▸ Invented words related to happy as a clam