Claim to know nurse (7)
I believe the answer is:
contend
'claim' is the definition.
(synonyms)
'know nurse' is the wordplay.
'know' becomes 'con' (I am not sure about this - if you are sure you should believe this answer much more).
'nurse' becomes 'tend' (I've seen this in another clue).
'con'+'tend'='CONTEND'
'to' acts as a link.
Can you help me to learn more?
(Other definitions for contend that I've seen before include "Struggle; assert" , "Maintain" , "Debate - contest - claim" , "Struggle in rivalry" , "Compete, vie" .)