吸う
すう · suu · JLPT N5 · verb-godan
to suck
🥤 suu = the sooo sound of sucking air or a drink through a straw
Say suu slowly and your lips already purse and pull air in, so the word acts out its own meaning. The kanji 吸 has the mouth radical 口 on the left, marking it as a mouth action: breathing in, sucking, or smoking.
吸 — mouth radical 口 + reach 及 (phonetic)
吸 is a phono-semantic compound. The mouth radical 口 signals the meaning—an action done with the mouth—while 及 (jí) hints at the original sound. It depicts drawing air or liquid in through the mouth, giving the modern senses 'inhale, suck, absorb'.