Directive popular with union (10)

I believe the answer is:

injunction

'directive' is the definition.
(thesaurus)

'popular with union' is the wordplay.
'popular' becomes 'in'.
'with' says to put letters next to each other.
'union' becomes 'junction' (junction is a kind of union**).
'in'+'junction'='INJUNCTION'

(Another definition for injunction that I've seen is " Order".)

I've seen this clue in The Telegraph.

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