Grumpy, I will go along with editor (3,8)

I believe the answer is:

ill humoured

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'grumpy' is the definition.
Both the definition and answer are adjectives. Maybe you can see a link between them that I can't see?

'i will go along with editor' is the wordplay.
'i will' becomes 'I'll' (abbreviation).
'go along with' becomes 'humour' (I've seen this before).
'editor' becomes 'ed' (abbreviation).
'ill'+'humour'+'ed'='ILL-HUMOURED'

Can you help me to learn more?

(Another definition for ill humoured that I've seen is " bad tempered".)

I've seen this clue in The Times.

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