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"Descriptions about “What kind?” add detail about the qualities of the noun or pronoun being described. This ranges from details regarding physical characteristics to emotional states. Here are some examples: the yellowdress, the sad clown, the smart pupil."
Modifiers: Adjectives and Adverbs | Boundless Writing
What does "qualities" mean in simple words in "the qualities of the noun..." in the given context?
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It's a poor way of saying "properties".

When we talk of the properties of a word, we are referring to the syntactic characteristics of a word in a phrase or clause, such as what dependents does it take and how is it functioning.

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JigneshbharatiWhat does "qualities" mean in simple words in "the qualities of the noun..." in the given context?

I think they actually mean the qualities (properties, characteristics, aspects) of the referent of the noun, i.e., qualities of the entity in the real world that the noun refers to.

A house may have qualities like size and color. (the big house; the white house)
An athlete may have qualities like strength, height, weight, and speed. (a tall footballer; a strong boxer; a fast runner)
A lecture may have qualities like length and interest. (a long lecture; a boring speech)

And so on.

CJ