Question

what is the adjective of things​

Answer 1

In linguistics, an adjective is a word that modifies a noun or noun phrase or describes its referent. Its semantic role is to change information given by the noun. Adjectives are one of the main parts of speech of the English language, although historically they were classed together with nouns. 

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Answer 2

Below the past participle and present participle form for the verbs things and thingify which may be used as adjective of things.