I treat terrible habit (6)

I believe the answer is:

attire

'habit' is the definition.
(thesaurus)

'i treat terrible' is the wordplay.
'terrible' is an anagram indicator.
'i'+'treat'='itreat'
'itreat' is an anagram of 'ATTIRE'.

(Other definitions for attire that I've seen before include "Wear" , "12" , "Special clothing" , "I treat badly the dress." , "(To) dress; fine clothes" .)

I've seen this clue in The Telegraph.

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