Is imitated an pronoun

No, the Word 'imitated' is the past participle, past tense of the verb to imitate. The past participle of the verb also functions as an adjective.

Examples:

John imitated the mannerisms of his teacher. (verb)

It's the most imitated brand on the market. (adjective)

A pronoun is a Word that takes the place of a noun in a sentence, for example:

When John is hungry, he stands in front of the open refrigerator. (the pronoun 'he' takes the place of the noun 'John' in the second part of the sentence)