well (in good health): I’m very well, thank you.
healthy (in good health): Boil the bones, and the broth will keep you healthy.
all right informal (not ill, not hurt): Jane was ill, but she is all right now.
fine not used before a noun (in good health or reasonably happy): I am fine, how are you?
robust (strong and healthy): He was over 80 but still very robust.
fit (in good physical condition, especially because you exercise regularly): Swimming twice a week keeps me fit.
fit as a fiddle (very healthy and strong): You look fit as a fiddle.
hale and hearty (strong and healthy): Getting up early to exercise every day keeps me hale and hearty.
vigorous (strong, healthy, and full of energy): The vigorous trees grow more quickly.