Funny, a reflection (7)
I believe the answer is:
amusing
'funny' is the definition.
(I've seen this before)
'a reflection' is the wordplay.
'reflection' becomes 'musing' ('musing' can be a synonym of 'reflection').
'a'+'musing'='AMUSING'
(Other definitions for amusing that I've seen before include "Killing" , "Droll" , "might be funny" , "comic" , "Causing a smile" .)