School yet to deal with inflammation (4)
I believe the answer is:
stye
'inflammation' is the definition.
(I've seen this before)
'school yet to deal with' is the wordplay.
'school' becomes 's' ().
'to deal with' indicates anagramming the letters (to deal with can mean to tidy up or sort out).
'yet' anagrammed gives 'tye'.
's'+'tye'='STYE'
(Other definitions for stye that I've seen before include "Eyelid sore" , "Eye blemish" , "Seeing problem" , "Eye complaint" , "Ocular affliction" .)