Fear of treater of nippers (perhaps nip too bad — ooh, nasty!) (12)

I believe the answer is:

odontophobia

'fear of treater of nippers' is the definition.
(fear of dentists - dentists treat teeth or nippers)

'nip too bad ooh nasty' is the wordplay.
'nasty' is an anagram indicator (a nasty or wrong spelling).
'nip'+'too'+'bad'+'ooh'='niptoobadooh'
'niptoobadooh' is an anagram of 'ODONTOPHOBIA'.

'perhaps' acts as a link.

(Another definition for odontophobia that I've seen is " aversion to ivories".)

I've seen this clue in The Guardian.

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