Was of service when a few were sick (7)
I believe the answer is:
availed
'was of service' is the definition.
I can't tell whether this definition defines the answer.
'a few were sick' is the wordplay.
'few' becomes 'v'.
'were sick' becomes 'ailed' ('ail' can be a synonym of 'be sick').
'a'+'v'+'ailed'='AVAILED'
'when' acts as a link.
Can you help me to learn more?
(Other definitions for availed that I've seen before include "Profited from" , "Helped" , "Used to one's advantage" , "Used, put into service" .)