Negligent during entire mission (6)

I believe the answer is:

remiss

'negligent' is the definition.
(similar in meaning)

'during entire mission' is the wordplay.
'during' indicates the answer is hidden within the clue.
'REMISS' is hidden within 'entire mission'.

(Other definitions for remiss that I've seen before include "Negligent, derelict" , "Lacking attention to duty" , "Failing in one's duty" , "Neglectful" , "Negligent in performing duties" .)

I've seen this clue in The Daily Express.

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