Give up introducing complex rating scale (10)
I believe the answer is:
centigrade
'scale' is the definition.
(I've seen this before)
'give up introducing complex rating' is the wordplay.
'give up' becomes 'cede' ('cede' can be a synonym of 'give up').
'introducing' is an insertion indicator (some letters introduced or inserted into others).
'complex' indicates an anagram.
'rating' with letters rearranged gives 'ntigra'.
'cede' going around 'ntigra' is 'CENTIGRADE'.
(Other definitions for centigrade that I've seen before include "scale" , "C" , "measure of warmth" .)