Strange affectation to toss coin on silk (7)
I believe the answer is:
taffeta
'silk' is the definition.
(I've seen this before)
'strange affectation to toss coin' is the wordplay.
'strange' is an anagram indicator.
'to toss' suggests deleting specific letters.
'affectation' with 'coin' removed is 'affetat'.
'affetat' with letters rearranged gives 'TAFFETA'.
'on' is the link.
(Other definitions for taffeta that I've seen before include "Stiff, silky fabric" , "Fine crisp silk fabric" , "Fine crisp lustrous fabric" , "Stiff shiny material" , "Thin crisp lustrous silk" .)