Sees bid lost in addition (7)
I believe the answer is:
besides
'in addition' is the definition.
(I've seen this in another clue)
'sees bid lost' is the wordplay.
'lost' indicates an anagram.
'sees'+'bid'='seesbid'
'seesbid' is an anagram of 'BESIDES'.
(Other definitions for besides that I've seen before include "to boot" , "See bids (anag)" , "Apart from" , "Moreover" , "Anyway" .)