Boo Is A Gender-neutral Name Of American Origin. A Popular Term Of Endearment During The 90s And Early 2000s, Boo Has Become A Name In Its Own Right. Short And Sweet, This Cute Moniker Makes A Playful Choice For Your Little One. If Youre A Fan Of Animated Films, You May Recognize Boo As The Young Girl From Monsters, Inc. Whatever You Take From It, A Name Like Boo Is Sure To Make Baby Stand Out From The Crowd.