State of health (6)
I believe the answer is:
fettle
'state of health' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for fettle that I've seen before include "Be in fine . . . . . . to be in excellent form" , "Condition or trim, often fine" , "Condition (usually fine)" , "A state of fitness and good health" , "Condition, trim - best when fine" .)