annoyance vs pain in the ass

annoyance and pain in the ass both are nouns.

Word	Noun	Adjective	Verb	Adverb
annoyance	Yes	No	No	No
pain in the ass	Yes	No	No	No

As nouns, annoyance and pain in the ass are synonyms defined as:

annoyance and pain in the ass: something or someone that causes trouble; a source of unhappiness

Other synonyms of annoyance include bother, botheration, infliction, nuisance, pain, pain in the neck.

annoyance (noun)	pain in the ass (noun)
the act of troubling or annoying someone	something or someone that causes trouble; a source of unhappiness
something or someone that causes trouble; a source of unhappiness
anger produced by some annoying irritation
an unpleasant person who is annoying or exasperating
the psychological state of being irritated or annoyed