Straighten out former nurse (6)
I believe the answer is:
extend
'straighten' is the definition.
(I know that extend is a kind of straighten)
'former nurse' is the wordplay.
'former' becomes 'ex' (prefix meaning former or onetime).
'nurse' becomes 'tend' (tend can mean to nurse or look after).
'ex'+'tend'='EXTEND'
'out' acts as a link.
(Other definitions for extend that I've seen before include "continue" , "Stretch out - enlarge" , "Provide challenge" , "Stretch out, say the hand of friendship" , "Carry on" .)