Choose second vote (6)
I believe the answer is:
select
'choose' is the definition.
(synonyms)
'second vote' is the wordplay.
'second' becomes 's' (common abbreviation).
'vote' becomes 'elect'.
's'+'elect'='SELECT'
(Other definitions for select that I've seen before include "Of superior quality" , "Choose from several" , "Appoint" , "Carefully chosen; choose" , "Choose, being special" .)