I live with cross creature (4)
I believe the answer is:
ibex
'creature' is the definition.
(I've seen this before)
'i live with cross' is the wordplay.
'live' becomes 'be' (synonyms).
'with' says to put letters next to each other.
'cross' becomes 'x' (X is cross-shaped).
'i'+'be'+'x'='IBEX'
(Other definitions for ibex that I've seen before include "Mountain animal" , "Mountain goat with long curved horns" , "Large-horned wild goat" , "Wild goat of North Africa" , "Wind goat of North Africa" .)