Meaning
2 sensesA low-pitched beeping sound.
(colloquial)A gentle or playful tap or strike, especially on the nose.
Examples
3 sentencesHe wouldn't let me boop him.
I could boop boobs but I prefer to toot tits.
Boop! Got you on your nose. You'll have to be faster than that.
Origin
Imitative; compare beep.Imitative; compare beep.
Wiktionary, CC BY-SA 4.0 · source