Demonstrative pronouns are pronouns that point to specific things. "This, that, these, those, none and neither" are Demonstrative Pronouns that substitute nouns when the nouns they replace can be understood from the context. At the same time, to indicate whether they are close or far, in space or time, from the speaker in the moment of speaking. They also indicate whether they are replacing singular or plural words. Some grammars describe them as members of the class of function words called "determiners", since they identify nouns and other nominals. got it from google. want examples?
A demonstrative pronoun points to and identifies a noun or a pronoun. It is a single or distinct demonstrative word which substitutes of a noun, a noun phrase, a series of noun phrases, an activity or action, or a situation or state in both written and spoken English.