Hybrid of rodent and ox, very close! (4,4)
I believe the answer is:
next door
'very close' is the definition.
Both the answer and definition are adverbs. Perhaps you can see an association between them that I don't see?
'hybrid of rodent and ox' is the wordplay.
'hybrid of' is an anagram indicator (I've seen 'hybrid' mean this (I've seen this in other clues)).
'and' means one lot of letters go next to another.
'rodent'+'ox'='rodentox'
'rodentox' anagrammed gives 'NEXT-DOOR'.
Can you help me to learn more?
(Other definitions for next door that I've seen before include "Neighbours' house" , "Usual location of nearest neighbour" , "The adjacent residence" , "Neighbouring house" , "In the adjacent house" .)