Drive second towards flag (4)
I believe the answer is:
spin
'drive' is the definition.
(thesaurus)
'second towards flag' is the wordplay.
'second' becomes 's' (common abbreviation).
'towards' says to put letters next to each other (I've seen this in other clues).
'flag' becomes 'pin' ('pin' can be a synonym of 'flag').
's'+'pin'='SPIN'
(Other definitions for spin that I've seen before include "Work natural fibres into a thread or twist a story" , "Political interpretation; rotate" , "Rapid revolution" , "Rotate repeatedly" , "Massaging of news" .)