Worry about to wear off (4)
I believe the answer is:
fret
I believe this is a double definition.
'worry' is the first definition.
(fretting is a kind of worrying)
'to wear off' is the second definition.
(thesaurus)
'about' acts as a link.
(Other definitions for fret that I've seen before include "Anguish" , "Worry about doing woodwork?" , "Worry unnecessarily" , "Split up" , "Be anxious; ornament" .)