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...
The part of speech for this particular word is a noun.
part of speech
The part of speech for "answer" is a noun.
what part of speech is beneath
adverb
peak a boo
baby boo
baby boo
The part of speech for "explicit" is an adjective.
The part of speech for "lecturer" is a noun.