摸得到的滑
這是畫面本身，還沒搬到說話上。
adjective · C2
Smooth and slippery to touch or to walk on. This is the old, physical meaning, and you meet it mostly in writing from earlier centuries.
滑溜的
核心畫面
One way to hold this word: a surface that nothing holds onto. Ice on a path, wet stone, a fish in your hands — it all goes straight past, and there is no moment where anything catches. Now move that same surface into talk. Words that come out with nothing catching have not touched the hard part of the question; a speaker whose talk never catches has never had to stop and think; and if the smoothness is aimed at a listener, it carries them past their own doubts before they can stop either. The picture does not change from meaning to meaning. What changes is who is doing the sliding, and who it costs.
可以想成：一個什麼都抓不住的表面。結冰的小路、濕掉的石階、手裡的一條魚——東西一路滑過去，沒有任何一個地方卡得住。現…更多收起
可以想成：一個什麼都抓不住的表面。結冰的小路、濕掉的石階、手裡的一條魚——東西一路滑過去，沒有任何一個地方卡得住。現在把同一個表面搬到「說話」上。話滑出來，中間什麼都沒卡到，就是沒碰到問題最難的那一塊；一個人講話從來不卡，就是他從來不必停下來想；而如果那份滑是對著聽的人來的，它會在對方停下來懷疑之前，先把人帶過去。畫面從頭到尾沒有換。換的只是誰在滑，以及這一滑讓誰吃虧。From the word’s history
A shortening of the obsolete English glibbery 'slippery', or of its source, Low German glibberig / Dutch glibberig 'slippery'.
來自舊英文 glibbery（滑溜的）的縮寫，或直接來自它的源頭——低地德語 glibberig、荷蘭語 glibberig，意思都是「滑」。
Wiktionary entry for glib, etymology 1 (packet etymology_text): 'A shortening of either obsolete English glibbery (slippery) or its source, Low German glibberig, glibberich / Dutch glibberig (slippery).'
Two branches
話講起來太滑
同一個表面搬到語言上：滑的東西從話變成人，再變成對聽者施力的手段。三個意思都帶批評。
adjective · C2
Used about words, answers or opinions that come out smoothly and quickly but ignore how hard the real problem is. The speaker is criticising them.
說得順卻沒想清楚的