Conventional old hot rod smashed times (8)
I believe the answer is:
orthodox
'conventional' is the definition.
('orthodox' can be similar in meaning to 'conventional')
'old hot rod smashed times' is the wordplay.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'smashed' indicates anagramming the letters.
'times' becomes 'x' (multiplication sign).
'hot'+'rod'='hotrod'
'hotrod' anagrammed gives 'rthodo'.
'o'+'rthodo'+'x'='ORTHODOX'
(Other definitions for orthodox that I've seen before include "Conforming with established opinions" , "Adhering to what is commonly accepted" , "Conforming with tradition" , "Conformist" , "not Independent-minded?" .)