Terminology

Time

 * newleaf - the season of spring
 * greenleaf - the season of summer
 * leaf-fall - the season of autumn
 * leaf-bare - the season of winter
 * moon - the time between one full moon and the next (eg. two moons ago)
 * sunrise - one day long (eg. one sunrise ago)
 * heartbeat - a second
 * moonhigh - when the moon is highest in the sky
 * moonrise - when the moon rises
 * sunup - dawn
 * sunhigh - when the sun is highest in the sky
 * sundown - when the sun sets
 * half-moon - half a month; when the moon shows only one side
 * claw-moon - crescent moon
 * quarter-moon - a week

Distance

 * sun-rising-sky - east
 * sun-fleeing-sky - west
 * fox-length - the length of a fox (80 cm)
 * kittenstep - the length of a kit's step (1-3 cm)
 * pawstep - the length of a warrior's step (15 cm)
 * tail-length - the length of a cat's tail (25 cm)
 * rabbit hop - the length of a rabbit's hop (35 cm)
 * rabbit-length - the length of a rabbit (40 cm)
 * mouse-length - the length of a mouse (8-10 cm)
 * tree-length - the length of a tree
 * RiverClan: alder (28 m)
 * ShadowClan: pine (30 m)
 * ThunderClan: oak (30 m)
 * WindClan: birch (30 m)

General

 * cleanpaw - someone who sticks to the rules closely (scornful)
 * crowfood - something that is disgusting, like rotting prey (harsh)
 * crowfood-eater - someone who does not deserve to eat fresh prey (harsh)
 * dirtface - a general insult (harsh)
 * flea-brain - a general insult (friendly, usually teasing)
 * foxbreath - exclamation
 * fox-dung - exclamation or insult (harsh)
 * fox-heart(ed) - someone cold, cruel, or evil (harsh)
 * furball - insult (friendly, teasing)
 * Great StarClan! - exclamation for surprise or anger
 * how in Silverpelt? - exclamation of surprise
 * in all the stars! - exclamation
 * make dirt - go to the toilet
 * mouse-brain - insult (friendly, usually teasing)
 * mouse-breath - insult (rude)
 * mouse-dung - exclamation
 * mouse-heart(ed) - someone who is cowardly
 * mousefodder - someone who is worthless, often a kittypet (harsh)
 * mousedust - something insignificant and small, or shredded beyond recognition
 * pain in the tail - someone who is annoying
 * scaredy-mouse - someone who is cowardly

RiverClan

 * as easy as swallowing a minnow - something that is very easy
 * drypaw - someone who dislikes getting wet
 * frog-dung - exclamation or insult (harsh)
 * frog-dirt and fish-guts! - exclamation when something goes wrong
 * minnow-brain - insult (friendly, teasing)
 * snake-heart(ed) - someone cold, cruel, or evil (harsh)

ShadowClan

 * bat-blind - someone who is not looking where they're going
 * rabbit-chasers - a WindClan cat
 * snake-heart(ed) - someone cold, cruel, or evil (harsh)
 * snake-tongue - someone who should not be believed (harsh)
 * toad-brain - insult (friendly, usually teasing)

ThunderClan

 * dormouse - someone who sleeps a lot

WindClan

 * feather-brain - insult (friendly, usually teasing)
 * hare-brain - insult (friendly, usually teasing)
 * hare-dung - exclamation
 * rabbit-brain - insult (friendly, usually teasing)

Expressions

 * as much use as a dead fox - something that is useless
 * bees in their brain - someone is not making sense
 * didn't catch so much as a whisker - someone who is not a good hunter, or an exclamation that a patrol did not have good hunting
 * it's better to scare away a mouse than welcome a badger - nursery saying meaning it's better to scare a friendly cat than welcome an unfriendly cat
 * like JaguarClan/LeopardClan/LionClan/LynxClan/TigerClan - an expression for someone who did something exceptionally
 * madder than a fox in a fit - someone is not making sense
 * may StarClan light your path - an expression to wish someone well
 * may StarClan banish all the fleas from your nest - an expression of gratitude
 * may the sun warm your back and the fish leap into your paws - blessing used in RiverClan to wish good luck
 * may you find good hunting, swift running, and shelter when you sleep - a farewell
 * only StarClan knows - expression that the answer is impossible to know
 * once a kittypet, always a kittypet - (harsh) expression about how kittypets do not make fine warriors
 * sorry catches no prey - meaning apologies will not change the past
 * sorry fills no bellies - meaning apologies will not change the past
 * stir(ring) up a bee's nest - meaning a cat is looking for or starting trouble
 * tabbies don't change their stripes - meaning a cat does not change their nature
 * that's a load of badger droppings - harsh exclamation that something is nonsense
 * thistles and thorns! - exclamation when something goes wrong
 * what in StarClan's name? - an expression of confusion
 * wouldn't give a mousetail - exclamation meaning the cat does not care or someone is stingy
 * would've made mousemeat out of you! - expression to describe how dangerous an enemy is
 * would [do something] for a couple of mousetails - saying that they would do something for no reward
 * when hedgehogs fly - expression of disbelief
 * who made dirt in their fresh-kill/nest? - an expression about a moody cat
 * who ruffled their fur? - an expression about a moody cat
 * you fight/hunt like a kittypet! - an insult to insult someone's poor skills

Mythology

 * JaguarClan - a Clan of big spotted cats who hunted in forests
 * LeopardClan - a Clan of big spotted cats who hunted in grasslands
 * LionClan - a Clan of big cats with manes who hunted in grasslands
 * LynxClan - a Clan of big cats with pointed ears who hunted in forests
 * TigerClan - a Clan of big striped cats who hunted in wetlands