How is the word まさか used?


Plain and simple. The Jisho definition "by no means; never!; well, I never!;
you don't say!" doesn't seem to coincide with any of the sample sentences I
find either on Jisho or Tatoeba. Can someone please shine some light on the
meaning and usage of this word?

ありがとうございます！




I'm not really sure what you mean. Looking at the sample sentences at
jisho.org which are Tanaka/Tatoeba, they all fit roughly with that definition.

まさか is an exclamation, so it's going to be hard to provide an exactly
translation that explains how it's used, but I take it that it is used for
surprising information.

Looking at the first example:

> まさか、[嘘]｛うそ｝でしょう

I might translate it depending on the level of formality you want the English
to have as any of the following:

(1) Wow, you've got to be kidding! (2) No way, that's a lie right? (3) That's
unbelievable. It's a lie right?

* * *

I haven't really seen it used this way much which is also in the corpus (but
that could just be a limit of who I encounter and when):

> まさかの時のために彼は保険に加入した。

In these まさかの時 constructions, I take the meaning to be "unbelievable/unlikely
times"

= He insures himself for unlikely times.

