Some saw a keeper alert (5)

I believe the answer is:

awake

'alert' is the definition.
(I know that alert can be written as awake)

'some saw a keeper' is the wordplay.
'some' indicates a hidden word (some of the parts of the word are used).
'AWAKE' is hidden within 'saw a keeper'.

(Other definitions for awake that I've seen before include "Conscious and (usually) open-eyed" , "Alive and alert" , "Not asleep" , "Tossing and turning" , "Unable to sleep" .)

I've seen this clue in The Daily Express.

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