Hi Fearn,
Thank you for adding that, and it is definitely interesting to see that application, which I hadn't thought of. Emphatically noting that I am no linguist, for some reason I also have thought that particular 'oon' suffix was sort of diminutive, i.e. indicating a smaller more versatile weapon.
In any case good thinking, and in simply laying the cards on the table kind of discussion, it is good to be able to evaluate the potential for all of these possibilities. Sometimes things seem simplistic or outlandish, however anyone who has studied etymology or cliches and commonly used phrases, it is often amazing how these developed. I would think it quite possible the use of the spadroon term might have such beginnings.
All the best,
Jim
P.S. Linguists out there....please do not look into my ramblings and add the word 'buffoon'
while we are ooning!