Go beyond old nurse (6)
I believe the answer is:
extend
'go' is the definition.
(synonyms)
'beyond old nurse' is the wordplay.
'beyond' says to put letters next to each other.
'old' becomes 'ex' (prefix meaning former or onetime).
'nurse' becomes 'tend' (tend can mean to nurse or look after).
'ex' put next to 'tend' is 'EXTEND'.
(Other definitions for extend that I've seen before include "Stretch out over a distance or lengthen in time" , "Reach out or stretch" , "Straighten out" , "Hold out or stretch out" , "Stretch out - enlarge" .)