Nurse in bizarre sex case holds out (7)
I believe the answer is:
extends
'holds out' is the definition.
('extend' can be a synonym of 'hold out')
'nurse in bizarre sex' is the wordplay.
'nurse' becomes 'tend' (tend can mean to nurse or look after).
'in' indicates putting letters inside.
'bizarre' indicates anagramming the letters.
'sex' with letters rearranged gives 'exs'.
'tend' going within 'exs' is 'EXTENDS'.
'case' acts as a link.
This may not be correct. It may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for extends that I've seen before include "Makes longer" , "holds out" , "Widens" , "Enlarges" , "Reaches or stretches out, say the hand of friendship" .)