Noun: It is not just the name of any person,place or thing but also of any idea.
Adjectives: They describe the noun or a pronoun.
Adverb: They are similar to adjectives but we can find the difference that adj describe noun or a pronoun while adverb describe verb,adjective or other adverbs.
Preposition: They show relationship with time,location.
Interjections: The written or spoken expression of emotions of surprises, excitement,sadness etc