Unpleasant odour accompanying originally open toed footwear (4)
I believe the answer is:
boot
'footwear' is the definition.
(boot is a kind of footwear)
'unpleasant odour accompanying originally open toed' is the wordplay.
'unpleasant odour' becomes 'BO' (short for body odour).
'accompanying' means one lot of letters go next to another.
'originally' says to take the initial letters.
The initial letters of 'open toed' is 'ot'.
'bo'+'ot'='BOOT'
(Other definitions for boot that I've seen before include "Profit" , "Hard kick (colloq.)" , "Hard kick; part of car" , "Sack" , "Stout shoe" .)