Harry possesses silver, oddly (6)
I believe the answer is:
hassle
'harry' is the definition.
('hassle' can be a synonym of 'harry')
'possesses silver oddly' is the wordplay.
'possesses' becomes 'has' ('have' can be a synonym of 'possess').
'oddly' means one should take alternating letters.
The alternate letters of 'silver' are 'sle'.
'has'+'sle'='HASSLE'
(Other definitions for hassle that I've seen before include "Bug" , "Struggle" , "Informally, annoyance or quarrel" , "Informally annoy or bother" , "Modern word for bother and annoyance" .)