Dim market speculator holds onto pound (5)
I believe the answer is:
blear
'dim' is the definition.
(thesaurus)
'market speculator holds onto pound' is the wordplay.
'market speculator' becomes 'bear' (financial term).
'holds onto' is an insertion indicator.
'pound' becomes 'l'.
'bear' enclosing 'l' is 'BLEAR'.
(Other definitions for blear that I've seen before include "Baler (anag.)" , "Watery, blurred" , "Indistinct" , "Blur" , "Make (the eyes) dim" .)