Grunting, chew nuts — awful! (3-9)

I believe the answer is:
gut-wrenching
'awful' is the definition.
Both the answer and definition are adjectives.
Perhaps there's an association between them I don't understand?
'grunting chew nuts' is the wordplay.
'nuts' is an anagram indicator (nuts can mean crazy).
'grunting'+'chew'='gruntingchew'
'gruntingchew' anagrammed gives 'GUT-WRENCHING'.
Can you help me to learn more?
(Another definition for gut-wrenching that I've seen is " Extremely upsetting".)
I've seen this clue in The Times.
Want a hint initially instead of a full solution?
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