Expression of frustration about European taxes (5)
I believe the answer is:
rates
'taxes' is the definition.
(rate is a kind of tax)
'expression of frustration about european' is the wordplay.
'expression of frustration' becomes 'rats' ('rats' is an expression of annoyance).
'about' indicates putting letters inside.
'european' becomes 'E' (abbreviation e.g. EU).
'rats' going around 'e' is 'RATES'.
(Other definitions for rates that I've seen before include "Taxes paid by businesses to local authority" , "Tax paid by businesses to a local authority" , "Former means of local taxation" , "Esteems, values" , "Charges, deserves" .)