Taboo or??

[GunChleoc]

When you stub your toe, you can also say "Murt!", or a more colorful one, "Tòin an t-Sàtain!"

I got both of those from Lewis friends.

[GunChleoc]

About calling people names, check out https://www.academia.edu/2488427/Scotti ... nd_Edition_, section "3.4.3 Discourse Particles, Parenthetical Statements, and Interjections"

You might also enjoy The Naughty Little Book of Gaelic.

As to calling people names, male idiots are Amadain!, female idiots are Òinseach!

I don't know about friendly insults, as people are usually very polite. Might be more common for bilingual Gaels living in Glasgow though

[Droigheann]

Would it be usual to just shout "càc" as an expletive say after stubbing your toe or something?

Just came across it in a book: guy should have left a place before 7am, but when we checks his mobile after waking up:

"Cac! Tha e seachad air deich."

(However, the author is a apparently a learner, however advanced.)

[Fluffgar]

Would it be usual to just shout "càc" as an expletive say after stubbing your toe or something?

Just came across it in a book: guy should have left a place before 7am, but when we checks his mobile after waking up:

"Cac! Tha e seachad air deich."

(However, the author is a apparently a learner, however advanced.)

Sounds like a reasonably reliable source to me Language isn't a static thing anyway so I'm going to mark this as okay in my book. Taing.

[An Gobaire]

It would be more common among native Gaels to put it in a sort of vocative case.
It would also be more common to hear it after a mistake is made. E.g. a singer fluffing their lines or something like that.

"A chaca!"