is 止す (よす) somehow more "fancy" than 止める (やめる)?

Question

It seems to me that the most common way to say "stop" in Japanese is the verb 止める (やめる) and its intransitive form, but I've also seen 止す(よす) being used occasionally, and felt like it was a rarer form to use and was reserved for people with specific social hierarchic positions. I haven't found any answers regarding social nuances when using either verb anywhere else.

There must be more than one verb for a reason, so are there any rules of usage for both verbs and any social context they apply to?

Answer 1

By 止す, do you mean よす? It is almost always written in kana alone. Besides, 止める has two readings (とめる and やめる) and two meanings. Which do you refer to? You have to choose the right verb depending on the intended meaning:

• とめる: to stop doing something (that is already in progress) / to stop (a physically moving object)
• やめる: to refrain from doing something (usu. before starting it) / to quit (a habit, a company, etc) / to cancel (an event)
• よす: to refrain from doing something (usu. before starting it)

As you can see, よす and やめる can be interchangeable when they mean "to refrain from doing something".

• 行くのはよそう。
  ∼ 行くのはやめよう。
  Let's (change our plans and) not go.
• 冗談はよしてくれ。
  ∼ 冗談はやめてくれ。
  Stop joking!
• よしません？
  ∼ やめません？
  Why don't we think twice?

I think there is no difference in terms of fanciness or register. It is natural for anyone to use them, both in speech and in writing, as long as they are used correctly. The only difference I can see for now is that よす is almost always used in the context of requesting or suggesting. 彼は冗談をやめなかった is okay but 彼は冗談をよさなかった sounds awkward to me.