Here are some terms that you should learn to make your posts more interesting.

Stupid furball - usually a friendly teasing term between mates, Clanmates, and Clans; can also be an insult pretty much the same as calling someone a dummy
Bossy furball - an insult used to offend a cat who orders everyone about; can also be a teasing insult.
Bossy paws - another teasing insult
Slow slug - usually a friendly teasing term between Clanmates and Clans; can also be an insult same as calling someone a slowpoke
Mousebrain - an insult; can also be used as a teasing insult between Clanmates.
Mousedung - an insult; more offensive than mousebrain, but less offensive than foxdung.
Foxdung - an insult; more offensive than mousedung, more offensive than crowfood. It's also a swear. One would say it if one missed a catch or something.
When hedgehogs fly - a saying that means something is impossible, "when pigs fly".
When rabbits fly - a saying that means something is impossible.
Mouse-brained - term used to describe something silly or foolish.
Sharing tongues - term used to describe cats grooming each other and sharing news.
Kitscent - the smell of a kit.
milkscent - the smell of a queens milk
Newleaf - the season of spring
Greenleaf - the season of summer.
Leaf-fall - the season of autumn.
Leaf-bare - the season of winter.
Moon - about a month (from one full moon to another)
Moonhigh - the point in time when the moon is highest in the sky; midnight.
Sunhigh - the point in time when the sun is highest in the sky; noon.
Fresh-kill - freshly caught prey.
Crowfood - rotting, dead prey or garbage; also used as an insult, less offensive than foxdung.
Gathering - a meeting that the Clans hold in peace in a certain place (Fourtrees, the island) when the moon is at its fullest.
StarClan - the warrior ancestors of the Clans.
(The) Moonstone, Moonpool - a place where medicine cats and leaders meet and share dreams with StarClan, and where StarClan have a stronger connection.
Silverpelt - the large swath of stars in the sky (the Milky Way); StarClan is represented by Silverpelt.
Kittenstep - about an inch (or three centimeters)
Mouse-length - about two inches (about five centimeters)
Pawstep - about six inches (about fourteen centimeters)
Tail-length - about the length of a cat's tail (as in a tail-length away; a foot, which is about thirty centimeters)
Fox-length - about the length of a fox (around a yard or meter)
Rabbit-length - about the length of a rabbit (a bit less than a foot)
Thunderpath - a road used by Twolegs.
Monster - a human vehicle (cars, trucks, and other wheeled transportation tools; larger monsters are construction vehicles)
Water Monster - a human boat
Halfbridge - a dock.
Twoleg - a human.
Twoleg kit - a human child.
Twoleg nest - a human house.
Twolegplace - a human town.
Twoleg rubbish - human litter (trash).
Carrionplace - a human trash dump.
Greenleaf Twolegplace - a place where humans visit only in the summer, like a campsite or recreational place.
Horseplace - a horse ranch or stable.
Cutter - a veterinarian, usually one specialized in spaying and neutering.
"Green-pelt things" - a camping tent that humans sleep in
"Water-monster" - a motor-boat.
"Sun-drown-place"- the bay
Kittypet - Clan term for housecat. It can also be used as an insult; for example, "You're fighting like a kittypet."