Bootlicking soldiers following Sergeant Major (6)
I believe the answer is:
smarmy
'bootlicking' is the definition.
(I've seen this before)
'soldiers following sergeant major' is the wordplay.
'soldiers' becomes 'army' (group of soldiers).
'following' is a charade indicator (letters next to each other).
'sergeant major' becomes 'SM' (abbreviation for sergeant major).
'army' put after 'sm' is 'SMARMY'.
(Other definitions for smarmy that I've seen before include "Oleaginous" , "Unpleasantly suave or ingratiating" , "Smooth" , "Unctuous" , "Excessively flattering (R, not L)" .)