Is the word colors a pronoun?

No, the Word 'colors' is a noun or a verb.

The noun 'colors' is the plural form of the singular noun 'color'.

The verb 'colors' is the third person, singular, present of the verb to 'color'.

A pronoun is a Word that takes the place of a noun in a sentence.

Examples:

There were so many colors to choose from. (noun)

Kate colors her hair to lighten it. (verb)

Mother redecorated the kitchen. The colors she chose were blue and yellow. (the pronoun 'she' takes the place of the noun 'mother' in the second sentence)