Invariable French Adjectives ~ Adjectifs Invariables

In French, adjectives normally have to agree with the nouns they modify in gender and number. However, there are numerous adjectives which don't agree - they have a single form that does not change to reflect the gender or number of the noun. These are called invariable adjectives.

Invariable Color Adjectives

French color adjectives derived from nouns, such as animals, flowers, fruits, gems, and metals, are usually invariable:
amarante     amaranthine (dark purple-red)
ardoise     slate-grey
argent     silver
aubergine     eggplant
auburn     auburn
brique     brick-red
canari     canary yellow
caramel     caramel-colored
carmin     carmine
cerise     cherry red
chair     flesh-colored
champagne     champagne
chocolat     chocolate-brown
citron     lemon-yellow
crème     cream-colored
emeraude     emerald green
grenat     garnet
indigo     indigo
kaki     khaki
lavande     lavender
lilas     lilac
marine     navy blue
marron     brown
noisette     hazel
ocre     ochre
olive     olive-green
or     gold
orange     orange
pastel     pastel
pervenche     periwinkle
pie     (magpie) - piebald, black and white
pistache     pistachio-green
platine     platinum
prune     plum
puce     (flea) - puce
rouille     rust-colored
rubis     ruby red
sable     sandy, sand-colored
safran     saffron-colored
saphir     sapphire-blue
saumon     salmon-pink
tabac     tobacco brown
turquoise     turquoise
vermillon     vermilion
Exceptions:

1.  alezan (chestnut), fauve (tawny/fawn), incarnat (rosy), mauve, pourpre (crimson), rose (pink), vermeil (vermillion),and violet are variable according to the normal rules of agreement
2.  châtain (chestnut brown) is semi-invariable - it usually agrees in number, but rarely in gender

Multiple Colors

When two or more colors describe a noun, they may or may not agree:
1) If there are items of each individual color, the adjectives agree:

•  des drapeaux bleus, blancs, rouges - red, white, and blue flags (some are red, some are white, and some are blue)
• des chapeaux rouges et noirs - red and black hats (some are red and some are black)

2) If each item has all of the colors, the adjectives are invariable

• des drapeaux bleu, blanc, rouge - red, white, and blue flags (e.g., French flags)
• des chapeaux rouge et noir - red and black hats

This is one instance where agreement is useful, because it gives you more detail than what is available in the English translation.

Compound Colors

When adjectives of color are modified by another adjective or a noun, the adjectives are invariable:
une jupe gris clair     light gray skirt
des gants violet foncé     dark purple gloves
une couleur rouge-orange     reddish-orange color
des yeux bleu-vert     blue-green eyes
une voiture vert pomme     apple-green car
des fleurs rouge tomate     tomato-red flowers

Adjectives Borrowed From Other Languages

French adjectives borrowed from other languages are usually invariable:
ad hoc     ad hoc
a priori     a priori
antitrust     anti-trust
baby     baby
beat     beatnik
cantilever     cantilever
charter     charter
cheap     cheap (poor quality)
clean     clean
cool     cool
curriculum vitae     curriculum vitae, résumé
dance     related to dance music
design     designer
destroy     destroyed, trashed, wild
express     related to espresso
fahrenheit     Fahrenheit
free-lance     freelance
fun     fun
funky     funk
furax     furious
glamour     glamorous
gold     gold(en)
gore     gory
gratis     free
groggy     groggy
halal     halal (in accordance with shari'a principles)
hi-fi     hi-fi
high-tech     high-tech
hot     hot (jazz)
kascher     kosher (in accordance with Judaic principles)
kitsch     kitsch
indoor     indoor
inuit     Inuit
jazzy     jazz, related to jazz
kif-kif     same, identical
kitsch     kitsch
lambda     averge, typical
light     light, low in calories
marengo     Marengo
offset     offset
offshore     offshore
out     out of touch, (tennis) out
people     celebrity
pop     pop (music, art)
pro forma     pro forma
punk     punk
record     record
relax     relaxed, informal, laid back
revolving     revolving
select     select, high-class, posh
sexy     sexy
snob     snobby, snobbish
solo     solo
soul     soul (music)
sport     casual, athletic (clothes, shoes)
spot     (economics) spot
standard     standard
stand-by     stand-by
sterling     (pound) sterling
tango     bright orange
top     great, best
trash     trashy, base, tasteless
vaudou     voodoo
vidéo     video
waterproof     waterproof
zen     Zen