做得沒有破綻
同一個「完整」的畫面，從睡眠移到一個東西的結構或一段推理上。
r · C1
In a thorough, solid way, with nothing weak or missing, so that the thing built, argued or supported holds up when it is tested.
扎實地；站得住腳地
核心畫面
One way to hold this word: something whole, with no crack and no gap in it. A night's sleep with no waking in the middle. A wall with no weak brick. A defeat with no room left to argue. Every use is the same shape — nothing missing.
可以想成：一個完整的東西，上面沒有裂縫、沒有缺口。一夜的睡眠中間沒有醒過來；一面牆裡沒有一塊鬆掉的磚；一場敗仗沒有留…更多收起
可以想成：一個完整的東西，上面沒有裂縫、沒有缺口。一夜的睡眠中間沒有醒過來；一面牆裡沒有一塊鬆掉的磚；一場敗仗沒有留下可以爭的餘地。三種用法其實是同一個形狀——沒有缺的那一塊。From the word’s history
It is sound plus -ly, and the Old English ancestor ġesundlīċe meant safely or in good health; the modern senses appear from the sixteenth century. Whole and unharmed is still the picture underneath.
這個字可以想成 sound 加上 -ly。古英文的 ġesundlīċe 原本是「平安地、健康地」，現在這幾個意思是十六世紀以後才出現的。「整個好好的、沒有受損」這個底子一直沒變。
Wiktionary, entry 'soundly' etymology (packet source_ref kaikki:3f6f69a190036ae4:1209326037:6705)
From the picture
Also in this word
r · B2
If you sleep soundly, you sleep deeply and calmly, without waking up in the night and without anything troubling you.
（睡得）香甜安穩