Making an enemy of a right awful giant (10)

I believe the answer is:

alienating

'making an enemy of' is the definition.
(to alienate is to make a bad impression on)

'a right awful giant' is the wordplay.
'right' becomes 'lien' (I've seen this before).
'awful' indicates anagramming the letters.
'giant' with letters rearranged gives 'ating'.
'a'+'lien'+'ating'='ALIENATING'

(Another definition for alienating that I've seen is " Turning off".)

I've seen this clue in The Telegraph.

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