Noun(adjective) or adjective noun with multiple nearly same labels

1. What is an adjective noun combination?
2. What are compound nouns and adjectives?
3. Can same word be a noun & adjective?
4. What words can be used as nouns and adjectives?

What is an adjective noun combination?

A compound noun is a noun that is made with two or more words. A compound noun is usually [noun + noun] or [adjective + noun], but there are other combinations (see below). It is important to understand and recognize compound nouns.

What are compound nouns and adjectives?

Adjectives, verbs, prepositions, and nouns can all be described as compounds. As compounds, they are made of two or more existing words combined into one, such as housetop (noun), many-sided (adjective), playact (verb), or upon (preposition).

Can same word be a noun & adjective?

A few nouns look plural but we usually treat them as singular (for example news, billiards, athletics). When we use these nouns "as adjectives" they are unchanged: a news reporter, three news reporters. one billiards table, four billiards tables.

What words can be used as nouns and adjectives?

Verbals (infinitives, gerunds, and participles) often act like two different parts of speech. An infinitive (the “to” form of a verb) can function as a noun, adjective, or adverb. Specialists often call these “nominal infinitives,” “adjectival infinitives,” and “adverbial infinitives”: To err is human.