Rebellious boy chopped notch in twig (5,2)
I believe the answer is:
latch on
'twig' is the definition.
(I know that twig can be written as latch on)
'rebellious boy chopped notch' is the wordplay.
'rebellious' says the letters should be written in reverse.
'boy' becomes 'Al'.
'chopped' indicates an anagram (letters chopped or smashed up).
'al' written backwards gives 'la'.
'notch' is an anagram of 'tchon'.
'la'+'tchon'='LATCH ON'
'in' acts as a link.
(Other definitions for latch on that I've seen before include "Understand" , "door is locked" .)