In front of monarch, blow kiss (7)
I believe the answer is:
smacker
'kiss' is the definition.
(I know that kiss can be written as smacker)
'in front of monarch blow' is the wordplay.
'in front of' is a charade indicator (letters next to each other) (some letters go in front of others).
'monarch' becomes 'ER' (abbreviation for Elizabeth Regina, British Queen).
'blow' becomes 'smack' (both can mean a hit).
'er' put after 'smack' is 'SMACKER'.
(Other definitions for smacker that I've seen before include "someone taking part in strike?" , "Loud kiss - GBP1" , "pound" , "Loud kiss -- PS1" .)