The word proposal is a noun. It is something that is proposed for consideration.
The word successful is an adjective. It means to have accomplished whatever was previously proposed.
Quarantine Speech
Thomas Paine
The part of speech for this particular word is a noun.
part of speech
The part of speech for "answer" is a noun.
adverb
what part of speech is beneath
The part of speech for "unfamiliar" is an adjective.
The part of speech of "came" is a verb.
The part of speech for "twirl" is a verb.
The part of speech for "explicit" is an adjective.