Uncovered notice relating to the ear (4)
I believe the answer is:
otic
'relating to the ear' is the definition.
(I've seen this in another clue)
'uncovered notice' is the wordplay.
'uncovered' says to take the centre.
The centre of 'notice' is 'OTIC'.
(Other definitions for otic that I've seen before include "of concern to the listener" , "in relation to the listener" , "of lugs" , "about hearing" , "relating to area incorporating canal" .)