Repeatedly exclude one cold and brutal (8)
I believe the answer is:
barbaric
'brutal' is the definition.
(I've seen this before)
'repeatedly exclude one cold' is the wordplay.
'repeatedly' says to double the letters.
'exclude' becomes 'bar' (synonyms).
'one' becomes 'i' (Roman numeral).
'cold' becomes 'C' (eg on taps).
'bar' doubled is 'barbar'.
'barbar'+'i'+'c'='BARBARIC'
'and' acts as a link.
(Other definitions for barbaric that I've seen before include "Savage and cruel" , "Uncivilized" , "Rabbi car for rough and uncivilised" , "Cruel and brutal" , "Like 24 [BRUTE]" .)