Definitions

(onom.) to bubble
bo grammatical particle equivalent to 吧

Etymology

The sound  of ripples in the water  also provides the pronunciation

About

combines the mouth radical (kǒu), indicating an oral sound, with (bō, ripples in water), which provides the pronunciation and evokes the popping of bubbles. Used as an onomatopoeia, it represents sounds such as popping, bursting bubbles, or the smacking sound of a kiss. As a modern coinage without deep classical roots, it serves simply as a phonetic transcription for these short, explosive sounds made by the mouth or escaping air.