Curses musketeer over being posted to front (5)
I believe the answer is:
oaths
'curses' is the definition.
(I know this)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for oaths that I've seen before include "Solemn promises or curses" , "professions of loyalty" , "Solemn sworn promises" , "Swearwords" , "Cursing" .)