Upset, cancel court claim (5)
I believe the answer is:
exact
'claim' is the definition.
(I know that exact is a more specific form of claim)
'upset cancel court' is the wordplay.
'upset' says the letters should be written backwards.
'cancel' becomes 'axe' (I've seen this in another clue).
'court' becomes 'ct' (abbreviation used in road names).
'axe' written backwards gives 'exa'.
'exa'+'ct'='EXACT'
(Other definitions for exact that I've seen before include "Demand, extort" , "on the money" , "Faithful" , "Precise - demand" , "Spot-on" .)