
Cameron B. answered 02/25/21
M.A. with two years of Graduate Latin & Three Years of teaching
Jonathan,
Great Question!
Short Answer: No. Not at least in the way you want to use it. Spectrum is a noun and so using it as an adjective modifying milites is grammatically awkward in Latin. However, if you want a "ghostly" adjective to use, I'd recommend larualis, laruarle : Specter-like, deathly, ghostly ; Thus it would read, milites laruales.
Now, if you wanting to describe more the look, i.e. translucent/transparency, of the soldiers and not the "death" quality, then you have a few more options.
1) perspicuus, -ua, -uum : Transparent, clear ; milites perspicuī
2) perlucidulus, -a, -um : Transparent ; milites perlucidulī
If you really like spectrum, only way to use it is in a statement with tamquam [just as, like]. Thus, milites tamquam spectrum sunt [The soldiers are like/as specters].
Hope this helps!
Cameron Brock
Jonathan F.
Cameron, thanks for your throughly answer! It will certainly help me a great deal :) Yes I might instead use one of the other words that you mention.02/25/21