Noun -
A noun is a naming word. It can name anything, a person, animal, place, thing, quality, state, idea, etc.
Example -Boy, girl, honesty, river, rabbit, telephone etc.
Proper Noun-
A proper noun is the name of a particular person or thing.
Example- Shruti, Mount Everest, Taj Mahal etc.
* All proper nouns begin with a capital letter.
Common Noun-
A common noun is a name shared by every person or thing of the same class. It does not refer to any particular person or thing.
Example- Man, woman, tiger, tree, table etc.
Pronoun -
A pronoun is a word used in place of a noun or a noun phrase.
Example - He, She, They, We etc.