Wild ox thus getting into scrap (5)
I believe the answer is:
bison
'wild ox' is the definition.
(I've seen this before)
'thus getting into scrap' is the wordplay.
'thus' becomes 'so' (synonyms).
'getting into' is an insertion indicator.
'scrap' becomes 'bin' (I've seen this in other clues).
'so' inserted inside 'bin' is 'BISON'.
(Other definitions for bison that I've seen before include "O bins could be full of buffalo" , "Ox-like ruminant" , "US prairie cattle" , "Shaggy-haired wild ox" , "Big beast" .)