Apart from gradation (see a dedicated article), adjectives in Quertílian are not inflected. In neutral form, they end in -w.
Oriaw elu te qlúra. The tables are big.
Doenw elwe te aldi'eníra. The woman are wise.
In plural a mixed group is described with the masculine form.
Iweiw elil te itéra. The people are happy.
The adjective are postponed if they have a attributive function:
Andé em te ítel tonriw. This is an old castle.
It is fronted if it has a predicative function:
Tonriw em te ítel. The castle is old.
Two adjectives in coordinating relation (conjunctions is "and", mong "or," sé "but") can be turned into one, compound word (written with hyphens), and fronted:
Oriaw-is-tonriw em te ítel. The castle is big and old.
Gurqiw-mong-sogiw li'em? Is he stupid or evil?
Oriaw-sé-elhi'ew em te qurungq. The giant is big but nice.
If the adjective has further complements, the complements usually precede the adjective. In case of fronted adjectives, the complement remains after the noun.
Tonriw em te ítel erindi. The castle is very old.