Pronunciation: (hel'thē),[key] —adj.,health•i•er, health•i•est. 1. possessing or enjoying good health or a sound and vigorous mentality: a healthy body; a healthy mind. 2. pertaining to or characteristic of good health, or a sound and vigorous mind: a healthy appearance; healthy attitudes. 3. conducive to good health; healthful: healthy recreations. 4. prosperous or sound: a healthy business. 5. Informal.fairly large: I bought a healthy number of books.