Unchanging habit (7)

I believe the answer is:

uniform

This clue is a double definition.

'unchanging' is the first definition.
(thesaurus)

'habit' is the second definition.
(thesaurus)

(Other definitions for uniform that I've seen before include "Distinctive outfit" , "Official dress" , "Regular - soldier's dress" , "Unvarying kind of costume" , "what soldier wears?" .)

I've seen this clue in The Globe and Mail.

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