NOUN :- a noun is the name given to any person, place, thing or event.ex Mohan, Delhi, car.
PRONOUN :- it is the word used in the place of noun to avoid its repitition. ex. he, she, it.
VERB :- these are the words used to describe an action. ex. sit, walk
ADVERB :- these are the words that describe any verb
ex. slowly, fastly