Anti-labour act? (4-3)

I believe the answer is:

lock-out

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'anti-labour act?' is the definition.
I can't tell whether this definition defines the answer.

'anti-labour act?' is the wordplay.
'anti labour' becomes 'lock' (I am not sure about this - if you are sure you should believe this answer much more).
'act?' becomes 'out' (out is a kind of act).
'lock'+'out'='LOCK-OUT'

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

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