Healthy swimmer old for gala’s final (5)
I believe the answer is:
whole
'healthy' is the definition.
(similar in meaning)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for whole that I've seen before include "Integral" , "Entire, undivided" , "undamaged" , "In entirety" , "Total" .)