babysitter vs baby-sitter

babysitter and baby-sitter both are nouns.

Word	Noun	Adjective	Verb	Adverb
babysitter	Yes	No	No	No
baby-sitter	Yes	No	No	No

As nouns, babysitter and baby-sitter are synonyms defined as:

babysitter and baby-sitter: a person engaged to care for children when the parents are not home

Other synonyms of babysitter include sitter.

babysitter (noun)	baby-sitter (noun)
a person engaged to care for children when the parents are not home	a person engaged to care for children when the parents are not home