Wushu: Using the word "******" is not a good idea; its original meaning is no longer valid and has been replaced by a fairly “hateful” way of referring to those with special needs.
Excellent question, Wushu. Yes, "horse" and "******" are both nouns. And in this case, each is a predicate nominative -- a noun or pronoun that follows a linking verb and refers to the subject. Linking verbs can be followed by nouns or adjectives: e.g., "******" or "retarded."
The other interesting thing about predicate nominatives is that when they are pronouns, we use the subject