Boo is an interjection. When used as the name of a person, it is a proper noun.
how do you start a speech in a youth audience
Actually, Yes.. if your intestines are "backed up" you can have Bile come out of your mouth...
part of speech
The part of speech for this particular word is a noun.
The part of speech for "answer" is a noun.
adverb
what part of speech is beneath
peak a boo
baby boo
baby boo
The part of speech for "explicit" is an adjective.
The part of speech for "twirl" is a verb.