Upset the cop in referring to speech sounds (8)
I believe the answer is:
phonetic
'referring to speech sounds' is the definition.
'upset the cop in' is the wordplay.
'upset' indicates anagramming the letters.
'the'+'cop'+'in'='thecopin'
'thecopin' anagrammed gives 'PHONETIC'.
(Other definitions for phonetic that I've seen before include "(Spelling) as pronounced" , "Representing what's said" , "Relating to the sounds of spoken language" , "Pinch toe (anag.)" , "Relating to speech sounds" .)