Is tired a abstract noun

Answer 1

Yes, the word tired can be a predicate nominative when it 'renames' the subject. Predicate nominatives follow a 'linking' verb. Examples:

Mary is tired. (Mary = tired)

Mary became tired. (Mary > tired)

They were tired. (They = tired)

When used with a non-linking verb, tired is not a predicate nominative. Examples:

That dog is a tired old thing. (tired is an adjective modifying the object or the sentence)

The tired kids were ready for a nap. (tired is an adjective modifying the subject of the sentence)

Answer 2

No, the word 'tired' is the past participle, past tense of the verb to tire. The past participle of the verb also functions as an adjective.

Examples:

The baby tired quickly at the picnic. (verb)

We put the tired baby in the shade for a nap. (adjective)

The abstract noun form of the verb to tire is the gerund, tiring.