青蛙那一聲低啞的叫
這一族就是那個聲音本身，離字的來源最近。
verb · B2
If a frog croaks, it makes a deep, low, rough sound. Ravens and some other birds and animals croak too.
呱呱叫
核心畫面
Think of a sound that on its way out: low, rough, short, with no ring to it. A frog in a wet field at night makes exactly that sound, and the word is built to it. Once you can hear that , the rest of the word follows, because English uses it for any throat that produces the same thing — a raven's, or a person's when the voice has given out.
「croak」可以想成一個「刮出來」的聲音：低、粗、短，沒有餘音，聽起來像是從乾乾的喉嚨裡磨出來的。最典型的畫面是夜…更多收起
「croak」可以想成一個「刮出來」的聲音：低、粗、短，沒有餘音，聽起來像是從乾乾的喉嚨裡磨出來的。最典型的畫面是夜裡水田邊的青蛙，一聲，停一下，再一聲。這個字的長相本來就是照那個聲音造的。只要先聽見那個刮的質感，後面的用法都好懂——因為英文把它借給任何發出同樣聲音的喉嚨：烏鴉的，或是一個人聲音壞掉時的。From the word’s history
Wiktionary traces croak back through Middle English to Old English crācettan ('to croak'), and says the origin is onomatopoeic — the word was made to imitate the sound.
來源把 croak 一路追到古英語 crācettan（呱呱叫），並說它是擬聲而來的。也就是說，這個字是照著聲音造出來的，所以「聲音」本來就是它的核心，不是後來引申的。
Wiktionary entry for croak (kaikki:3f6f69a190036ae4:440608360:13827): 'back-formation from Old English crācettan (to croak) ... of onomatopoeic origin.'
Three branches
人喉嚨裡的沙啞
同樣的刮擦聲，只是換成人的喉嚨。喉嚨痛或太乾的時候，聲音出來的質感確實跟青蛙的叫聲很像，英文就直接借用了同一個字。
verb · B2
To speak in a low, rough voice, the way people sound when their throat is sore or very dry. You can croak on its own, or croak the words you manage to get out.
沙啞地擠出聲音
俚語：死、把人做掉
來源只標了 slang，沒有說明這一層是怎麼來的。一個好記的看法是：人臨終前喉嚨裡那一聲低啞，正是這個字本來就在講的聲音——但這是幫助記憶的想法，不是歷史上的證據。
verb · C1
To die. This is an informal, joking way of saying it, and it treats the death lightly, so people usually keep it away from anyone who is grieving.
掛了、翹辮子