Refers to a person employed to clean buildings, rooms, or public spaces. Neutral term.
The cleaner tidies up the office every morning.
He works as a janitor at a school.
清掃作業員 is a longer, more formal compound often used in official contexts or job titles, but 清掃員 is sufficient for everyday use.
Compound of 清掃 (cleaning) + 員 (member, person in a role). The exact historical derivation is straightforward; the word is a modern occupational term.