Evacuate work having turned up small dagger (7)

I believe the answer is:

poniard

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'small dagger' is the definition.
(I've seen this in another clue)

'evacuate work having turned up' is the wordplay.
'evacuate' becomes 'drain' (I can't justify this - if you can you should believe this answer much more).
'work' becomes 'op' (abbreviation for opus).
'having turned up' is a reversal indicator.
'drain'+'op'='drainop'
'drainop' written backwards gives 'PONIARD'.

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(Other definitions for poniard that I've seen before include "Slender dagger" , "A drop in (anag) - dagger" , "Thin knife" , "straight crease?" .)

I've seen this clue in The Times.

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