Cushy — Easy.  Soft.

Dixie — An oblong iron pot or box fitting into a field kitchen.  Used for cooking anything and everything.  Nobody seems to know why it is so called.

Doggo — Still.  Quiet.  East Indian derivation.

Doing in — Killing.

Doss — Sleep.

Duck walk — A slatted wooden walk in soft ground.

Dud — An unexploded shell.  A dangerous thing to fool with.

Dug-out — A hole more or less deep in the side of a trench where soldiers are supposed to rest.

Dump — A place where supplies are left for distribution.

Entrenching tool — A sort of small shovel for quick digging. 
Carried as part of equipment.

Estaminet — A French saloon or cafe.

Fag — A cigarette.

Fatigue — Any kind of work except manning the trenches.

Fed up — Tommy’s way of saying “too much is enough.”

Firing step — A narrow ledge running along the parapet on which a soldier stands to look over the top.

Flare — A star light sent up from a pistol to light up out in front.

Fritz — An affectionate term for our friend the enemy.

Funk hole — A dug-out.

Gas — Any poisonous gas sent across when the wind is right. 
Used by both sides.  Invented by the Germans.

Goggles — A piece of equipment similar to that used by motorists, supposed to keep off tear gas.  The rims are backed with strips of sponge which Tommy tears off and throws the goggle frame away.

Go west — To die.

Grouse — Complain.  Growl.  Kick.

Hun — A German.

Identification disc — A fiber tablet bearing the soldier’s name, regiment, and rank.  Worn around the neck on a string.

Iron rations — About two pounds of nonperishable rations to be used in an emergency.

Knuckle knife — A short dagger with a studded hilt.  Invented by the Germans.

Lance Corporal — The lowest grade of non-commissioned officer.

Lewis gun — A very light machine gun invented by one Lewis, an officer in the American army.

Light railway — A very narrow-gauge railway on which are pushed little hand cars.

Listening post — One or more men go out in front, at night, of course, and listen for movements by the enemy.

Maconochie — A scientifically compounded and well-balanced ration, so the authorities say.  It looks, smells, and tastes like rancid lard.

M.O. — Medical Officer.  A foxy cove who can’t be fooled with faked symptoms.

Mess tin — A combination teapot, fry pan, and plate.

Military cross — An officer’s decoration for bravery.

Military medal — A decoration for bravery given to enlisted men.

Mills — The most commonly used hand grenade.

Minnies — German trench mortar projectiles.

Napper — The head.

Night ’ops — A much hated practice manoeuvre done at night.