After ex moves, having no liability to Revenue (3-4)
I believe the answer is:
tax-free
'having no liability to revenue' is the definition.
'after ex moves' is the wordplay.
'moves' is an anagram indicator.
'after'+'ex'='afterex'
'afterex' is an anagram of 'TAX-FREE'.
(Other definitions for tax-free that I've seen before include "Exempt from duty" , "Without a levy" , "Not liable to duty" , "Exempt from levies" , "Exempt from tariffs" .)