Zero tax: one working gives applause (7)
I believe the answer is:
ovation
'applause' is the definition.
(I've seen this before)
'zero tax one working' is the wordplay.
'zero' becomes 'o'.
'tax' becomes 'VAT' (UK Value Added Tax).
'one' becomes 'I' (Roman numeral).
'working' becomes 'on' (on can mean working or activated).
'o'+'vat'+'i'+'on'='OVATION'
'gives' is the link.
(Other definitions for ovation that I've seen before include "Round of applause, may be standing" , "Enthusiastic applause, often standing" , "One's often standing" , "Enthusiastic applause, may be given standing" , "Prolonged applause" .)