words vs monologue

words and monologue both are nouns.

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

As nouns, monologue is a hyponym of words; that is, monologue is a word with a more specific, narrower meaning than words:

Other hyponyms of words include aside, cue, soliloquy, throwaway.

words (noun)	monologue (noun)
words making up the dialogue of a play	speech you make to yourself
an angry dispute	a (usually long) dramatic speech by a single actor
the text of a popular song or musical-comedy number	a long utterance by one person (especially one that prevents others from participating in the conversation)
the words that are spoken
language that is spoken or written