Is the word yours a reflexive noun?

No, the Word 'yours' is a possessive pronoun, a Word that takes the place of a noun for something that belongs to you. The possessive pronouns are: mine, yours, his, hers, its, ours, theirs.

Example:

Which car is yours?

Congratulations, the job is yours.

Yours is the bag with your initial on it.

A reflexive Word is a reflexive pronoun, not a noun. A reflexive pronoun is a Word that 'reflects' back to the subject antecedent. The reflexive pronouns are: myself, yourself, himself, herself, itself, ourselves, yourselves, themselves.

Example:

Dad made himself breakfast.

The Browns repaired the roof themselves.

Jane drove herself to the appointment.