monologue vs soliloquy

monologue and soliloquy both are nouns.

Word	Noun	Adjective	Verb	Adverb
monologue	Yes	No	No	No
soliloquy	Yes	No	No	No

As nouns, monologue and soliloquy are synonyms defined as:

monologue (noun)	soliloquy (noun)
speech you make to yourself	speech you make to yourself
a (usually long) dramatic speech by a single actor	a (usually long) dramatic speech intended to give the illusion of unspoken reflections
a long utterance by one person (especially one that prevents others from participating in the conversation)