Tax on diamonds is removed (7)
I believe the answer is:
excised
'is removed' is the definition.
(I've seen this before)
'tax on diamonds' is the wordplay.
I cannot quite see how this works, but
'tax' could be 'excise' (excise is a kind of tax) and 'excise' is located in the answer.
'diamonds' could be 'd' (abbreviation in card games) and 'd' is located in the answer.
No letters remain.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for excised that I've seen before include "Having charges" , "Cut out, removed by cutting away" , "Deleted" , "Taken out" .)