With nouns

Consider the sentence, "I'm scared of bears". You can change that sentence by adding an adjective before the noun "bears". Any adjective would work—red, angry, Italian, wet. Choose one that makes sense to you.

I'm scared of mechanical bears.

With pronouns

Adjectives can also be used with pronouns: He was sad, or I ate very few, or

Everyone is tired of hearing about foolish me and my adventures.

Be careful though when using adjectives with pronouns. They usually cannot be used directly before a pronoun, like ❌ big he. They can sometimes be used after indefinite pronouns:Somebody special asked about you.

With (some) verb forms

Some verb forms—notably the -ing form—can be used as nouns. When they are, they can be modified with adjectives.

Karen's constant drinking made the office an unpleasant place to work.

When using more than one adjective with a noun, there are two things to remember. First, you have to use adjectives in a certain order. You can say a dirty, red car  but not ❌ a red, dirty car. The "order of adjectives" rules are tricky, and too complicated to discuss here, but as a general rule the adjective that is most closely linked with the identity of the noun goes closest to it. Being "red" is more a defining characteristic of the car than being "dirty", so "red" goes closer to "car".

The second thing to remember is that you need to put commas between the separate adjectives, unless the adjective helps to define what type the noun is. So, although we would write a long, hot night—with commas between "long" and "hot"—we would write a long, hot summer night. There's no comma between "hot" and "summer", because although they're both adjectives, "summer" tells what type of night we're talking about, so it's almost closer to being part of the noun than an independent adjective.

One fact to remember about Engish is that sometimes the same word can be used in different ways. For example, "French" can refer to the people of France, or it can be an adjective that refers to things from or related to France. When in doubt about what type a word is, check the dictionary. In fact, ACTD.

Based on this, one might wonder whether it's okay to use a noun card as an adjective. Well, you can do it—the game won't prevent you—but you probably shouldn't. Other people who see it might consider it a mistake, and it does sort of go against the spirit of the game. If you have a noun card, the challenge is to use it as a noun, not repurpose it as an adjective. But, you shouldn't let this "rule" interfere with your creativity. For example, assume we have this sentence:

The Russian bears were fighting.

We could change it by adding a conjunction and an article (adjective):

The Russian and the bears were fighting.

That's a clever and creative way to use a conjunction and an adjective at the same time, and we shouldn't let some technicality (the color of "Russian" indicates it's an adjective, but now it's functioning as a noun) stop us.

Another way in which a noun can be used as an adjective is when we use its possessive form:

Bob's uncle is an archeologist.

As you can see from the color of "Bob's", it is still considered a noun, even though it's acting like an adjective (it gives an extra detail about the noun "uncle"—whose uncle? Bob's.)