Depending on the context of the sentence the word "unknown" can be either an adjective or a noun.
Adjective - The noise came from an unknown direction.
Noun - An unknown was cast in the starring role of the movie.
The word "something" is a pronoun. It is used to refer to an unspecified or unknown thing.
The word "somebody" is a pronoun. It is used to refer to an unspecified or unknown person.
The part of speech for the word "boulevard" is a noun.
The part of speech for this particular word is a noun.
It is not ANY part of speech, there is no such English word as "stroobly".
The word "something" is a pronoun. It is used to refer to an unspecified or unknown thing.
The word "somebody" is a pronoun. It is used to refer to an unspecified or unknown person.
The part of speech for this particular word is a noun.
The part of speech that the word my is used as is an adjective.
The part of speech for the word diplomacy is a noun.
H is a letter, not a word. To be a part of speech, it needs to be a word.
The part of speech for the word "boulevard" is a noun.
The part of speech for the word civilian is English grammar.
The word speech is a noun.
Someone is an indefinite pronoun, a word that takes the place of a noun for an unknown or unnamed person. Example: Someone will call you when your order comes in.
The part of speech for this particular word is a noun.
The word speech is a noun.