Feline name her cat tore off drainage basin (9,4)
I believe the answer is:
catchment area
'drainage basin' is the definition.
(synonyms)
'feline name her cat tore' is the wordplay.
I cannot really see how this works, but
'feline' could be 'cat' (cat is a kind of feline) and 'cat' is found within the answer.
'name' could be 'rea' and 'rea' is located in the answer.
This explanation may well be incorrect...
'off' is the link.
Can you help me to learn more?
(Other definitions for catchment area that I've seen before include "Region from which a school's pupils are drawn" , "Region served by hospital, school etc" , "Region from which people are allocated to a school, hospital etc" , "Region from which a river draws rain" , "Terrain from which a river is fed" .)