Challenge Conservative nurse (7)

I believe the answer is:

contend

'challenge' is the definition.
(I know that challenge is a more specific form of the action contend)

'conservative nurse' is the wordplay.
'conservative' becomes 'con' (abbreviation for Conservative).
'nurse' becomes 'tend' (tend can mean to nurse or look after).
'con'+'tend'='CONTEND'

(Other definitions for contend that I've seen before include "Engage in a struggle" , "fight" , "Struggle in rivalry" , "Struggle; assert" , "Compete, vie" .)

I've seen this clue in The Everyman puzzle in The Observer.

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