Dreadful pun our pal hated (9)

I believe the answer is:

unpopular

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'hated' is the definition.
Both the definition and answer are adjectives. Maybe there's an association between them I don't understand?

'dreadful pun our pal' is the wordplay.
'dreadful' is an anagram indicator.
'pun'+'our'+'pal'='punourpal'
'punourpal' anagrammed gives 'UNPOPULAR'.

Can you help me to learn more?

(Other definitions for unpopular that I've seen before include "Without general approval" , "unlike 27 [IN FAVOUR]" , "Lacking appeal" , "Not well-liked" , "having few friends" .)

I've seen this clue in The Sun.

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