I am looking for a derogatory term that can be used to describe a novice soldier/conscript who is awful at army-stuff. Something like cannon fodder but it should stress the incompetence of the described person, but it can't be a vulgarism.
It is meant to be a unit name for a game set in a fantasy-medieval setting.
Nowadays in the US, infantrymen are regularly known as grunts. That said, it may not be quite what you're after, as it relates to their position rather than implying incompetence.
The appropriate word is gomer.
Gomer: military slang. An inept or stupid colleague, especially a trainee.
There are a lot of names for a raw recruit:
What about: greenhorn
Can't believe this hasn't been posted. The term used pretty widely across all branches is:
BOOT
It is used as both noun and adjective. F***in' boot, That was a boot move. You're so boot.
It can even be applied to officers. "Boot Lieutenant".
I've heard my military friends use FNG
I found a fascinating WWII slang dictionary (a very quick read), and who knew that a rookie was AKA:
croot, recruit, yearo, trainee, draftee, selectee, bimbo, bozo, dude, John, dogface, bucko, poggie and once in a while called a soldier.
Whilst many of the soldier synonyms don't sound flattering, the only term that specifically addresses a new soldier's inexperience, and perhaps incompetence is a tent stretcher:
a rookie (who) has to learn
There were many general derogatory terms:
slig .... goop. Meaning Sucker, Low-brow, Idiot and Good-will-buster
bell tapper.... a sailor who is slow to man his post.
tin ear.... slow code receiver.
eightball.... a Marine slow on the pick-up creating confusion by caus- ing others to run into him.
goon .... slow on the pick-up caus- ing confusion.
gold brick.... a soldier who eats and sleeps well but has no desire for work.
jawbone.... a soldier who is great on theory but poor on practice.
-Dictionary of service slang, compiled by Park Kendall. ... . Kendall, Park.
If it's going to be in a fantasy medieval setting, how about words like peasant, peon, or commoner. This could represent the fact that this person isn't even a soldier by trade, and has just barely been conscripted from a civilian role. You could even add the word conscript to any of those to make it more obvious. peasant conscript, conscripted peon, whatever fits your needs.
These words even have been used in settings like this, in games such as warcrafts I and II.
I was going to suggest recruit, but that would play much better in a modern or futuristic setting. Still, it could be used in much the same fashion conscript was used above.
A snooker? Snooker was contemporary slang for a newly-joined cadet in the British Army c. 1872. Also allegedly giving rise to the name of a form of billiards or pool:
'It is commonly held that the word represents an allusive use of snooker [n.1, a newly joined cadet], first applied to the game by Col. Sir Neville Chamberlain (1856–1944), a subaltern in the Devonshire Regiment stationed at Jabalpur in central India in 1875, with reference to the rawness of the play of a fellow officer.' (OED)
During WWII, "sad sack" was used in the US Army. Might be a bit dated now.
"You're a Gomer Pyle, you're a Beetle Bailey"? I'm trying to think of recent movies where someone was incompetent as a soldier -- perhaps "You're a Private Benjamin"? You have to be careful where you use a derogatory term for a soldier, that you don't come across as slandering all people serving their country in the military.
Now, if this is for "a fantasy-medieval setting", all of the above might be too anachronistic (too modern). You'd probably have to research ancient and medieval literature for references to incompetent soldiers, and then that would probably not be "gotten" by most participants. Off the top of my head, I can't think of any well-known (in older literature) soldiers who could be made fun of because of their incompetence.
We used "NUB," for non-useful body, to refer to someone too new to be trusted to operate local systems.
A sometimes derogatory term for someone who has just arrived in boot camp, prior to basic training is tenderfoot. That is, someone who isn't used to "marching."
Gunnery Sergeant Hartman: Holy Jesus! What is that? What the fuck is that? WHAT IS THAT, PRIVATE PYLE?
Private Gomer Pyle: Sir, a jelly doughnut, sir!
Gunnery Sergeant Hartman: A jelly doughnut?
Private Gomer Pyle: Sir, yes, sir!
Gunnery Sergeant Hartman: How did it get here?
Private Gomer Pyle: Sir, I took it from the mess hall, sir!
Gunnery Sergeant Hartman: Is chow allowed in the barracks, Private Pyle?
Private Gomer Pyle: Sir, no, sir!
Gunnery Sergeant Hartman: Are you allowed to eat jelly doughnuts, Private Pyle?
Private Gomer Pyle: Sir, no, sir!
Gunnery Sergeant Hartman: And why not, Private Pyle?
Private Gomer Pyle: Sir, because I'm too heavy, sir!
Gunnery Sergeant Hartman: Because you are a disgusting fat body, Private Pyle!
Private Gomer Pyle: Sir, yes, sir!
Gunnery Sergeant Hartman: Then why did you try to sneak a jelly doughnut in your footlocker, Private Pyle?
Private Gomer Pyle: Sir, because I was hungry, sir!
Gunnery Sergeant Hartman: Because you were hungry...
[turns and addresses rest of platoon]
Gunnery Sergeant Hartman: Private Pyle has dishonored himself and dishonored the platoon. I have tried to help him. But I have failed. I have failed because YOU have not helped me. YOU people have not given Private Pyle the proper motivation! So, from now on, whenever Private Pyle fucks up, I will not punish him! I will punish all of YOU! And the way I see it ladies, you owe me for ONE JELLY DOUGHNUT! NOW GET ON YOUR FACES!
[rest of recruits get in front-leaning-rest position, Hartman turns to Pyle]
Gunnery Sergeant Hartman: Open your mouth!
[shoves jelly doughnut into PYLE's mouth]
Gunnery Sergeant Hartman: They're payin' for it; YOU eat it! Ready! Exercise!
This one is very specific, so it may not be what you're looking for.
Officers in the U.S. Army of the lowest rank (2nd Lieutenant) are given the derogative term by more experienced enlisted soldiers: "butter bars."
This name stems from their insignia (a single golden bar) and the derision from the oddity of experience in the chain of command. Where a 2nd Lt. has almost no experience in-combat at all (fresh out of the military academy), they still technically outrank an experienced enlisted soldier (e.g., a Sergeant). You can imagine that experienced enlisted soldiers are often less than happy with that situation.
Rereading your post, I doubt this term will be especially helpful. However, if your piece sets include insignia, you may be able to go the extra mile, as it were, and come up with a derogatory term based on it.
A misfit is someone who is not suited for the position they take, unable to adjust. A non-conformist. The term is often used to describe someone who either has an attitude problem and is unwilling to adapt, or simply does not have the necessary competence to adapt.
There are some terms already famous that might describe a unit of non-conforming or incompetent military personnel, and who may be used as cannon fodder, where no one in command really expects them to be successful.
Black Sheep was made famous as a unit name for a US Marine Corps fighter squadron consisting originally of unassigned pilots with no aircraft. Their original unit leader, Major Greg "Pappy" Boyington, was known as a heavy drinker. While they were not known for being incompetent (far from it), they viewed themselves as Boyington's Bastards, as if being of unrecognized heritage, and took the bar sinister as part of their unit insignia. They are well known as having been very non-conformist in their behavior, but history tells that they were extremely good as war fighters.
From the movie The Dirty Dozen. This is a war film from 1967 concerning the formation of small unit of soldiers convicted of felonies. They are collection with various attributes, including slow-witted, brawler, gentle-giant (easily enraged), murderer, mysoginist, religious fantic, and gang member having problems with authority:
Notable members include slow-witted Vernon Pinkley (Donald Sutherland); Robert Jefferson (Jim Brown), an African American soldier convicted of killing a man in a racial brawl; Samson Posey (Clint Walker), a gentle giant who becomes enraged when pushed; Joseph Wladislaw (Charles Bronson) a taciturn coal miner recruited for his ability to speak German, convicted of shooting his squad's medic; A.J. Maggott (Telly Savalas), a misogynist and religious fanatic; and Victor Franko (John Cassavetes), a former member of the Chicago organized-crime Syndicate who has extreme problems with authority.
From a deeply military family and my own combat in Nam, I submit:
No description in living memory would strike real in a medieval setting. Slang just doesn't endure time. I concur that a non-vulgar term would be almost impossible to imagine. I've pondered it and think the reason is this: a soldier unreliable by either choice or natural limitation is an immediate existential threat to him/herself and everyone around them. Soldiers will not tolerate it and this is particularly true in combat. (One screw up can kills hundreds of people. Think GA Custer.) Often this is perceived by the group in an innate way they could not label. It is a harsh truth. Killing and dying is harsh. If the offender is not removed by some gentler means, they are often killed immediately by their frustrated and fearful peers at the first opportunity (fragging). These people are actually more dangerous than the enemy. No descriptor is too harsh. This is why you and I can't come up with a word that isn't sanitized.
Best I can think for your situation is Hollywood's sanitized "in hack" B-17 in Twelve O'clock High; "Leper Colony." Better yet, try anything by Bernard Cornwell for some clues.
CROW is sometimes used: Combat Recruit Of War
