Creep about to split with her (7)
I believe the answer is:
slither
'creep' is the definition.
(thesaurus)
'about to split with her' is the wordplay.
'about' shows that the letters should be reversed in order.
'to split with' becomes 'tils' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'tils' reversed gives 'slit'.
'slit'+'her'='SLITHER'
Can you help me to learn more?
(Other definitions for slither that I've seen before include "Quietly advance" , "Slide on slippery surface" , "Snake along" , "Move smoothly over a surface with a twisting motion" , "Slide (like a snake)" .)