Period of recovery after illness (13)
I believe the answer is:
convalescence
'period of recovery after illness' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for convalescence that I've seen before include "(Time of) gradual recovery of health" , "Period of recovery from illness" , "on the way to recovery" , "Recovery of health and strength" , "Recuperation (from illness)" .)