Bill has coin with special significance (6)
I believe the answer is:
accent
'special significance' is the definition.
'accent' can be an answer for 'significance' (thesaurus). I'm not sure about the 'special' bit.
'bill has coin' is the wordplay.
'bill' becomes 'ac' (short for account).
'has' is a charade indicator (letters next to each other).
'coin' becomes 'cent' (cent is a kind of coin).
'ac'+'cent'='ACCENT'
'with' is the link.
Can you help me to learn more?
(Other definitions for accent that I've seen before include "it could be grave" , "Stress, emphasis" , "Distinctive way of pronouncing language" , "Underline" , "Distinctive way of talking" .)