Brief illness - flu perhaps? (11)
I believe the answer is:
curtailment
'flu perhaps?' is the definition.
I can't judge whether this defines the answer.
'brief illness' is the wordplay.
'brief' becomes 'curt' (synonyms).
'illness' becomes 'ailment' (an ailment is an illness or health problem).
'curt'+'ailment'='CURTAILMENT'
Can you help me to learn more?
(Other definitions for curtailment that I've seen before include "Contraction" , "Terminal cut (anag) - downsizing" , "premature end" , "Abridgement, shortening" , "Bringing to an end" .)