Architect's trade vehicle, brown and horrible (8)
I believe the answer is:
vanbrugh
'architect's' is the definition.
(17th-century architect John Vanbrugh)
'trade vehicle brown and horrible' is the wordplay.
'trade vehicle' becomes 'van' (vehicle used by tradesmen).
'brown' becomes 'br' (electronics abbreviation).
'and' says to put letters next to each other.
'horrible' becomes 'ugh' (expression of disgust).
'van'+'br'+'ugh'='VANBRUGH'
(Other definitions for vanbrugh that I've seen before include "Playwright and architect of Blenheim Palace" , "Blenheim, Castle Howard architect" , "Sir John --, English baroque architect" .)