吐く
はく · haku · JLPT N3 · verb-godan
to throw up
🤮 吐く haku sounds like hack: you hack up your lunch
The kanji 吐 = 口 mouth + 土 earth: what leaves the mouth and lands on the ground. Haku also means to exhale or spit out, as in 息を吐く (iki wo haku, to breathe out). Vomiting is the strongest version of that.
吐 — mouth radical 口 + earth 土 (phonetic)
吐 is a phonosemantic compound: 口 (mouth) gives the meaning—an action done with the mouth—while 土 (tǔ) supplies the sound. Originally it meant to spit out or expel from the mouth, and it still covers spitting, vomiting, and by extension uttering or pouring out words.