I would set Irish Setter (possibly with a non-breaking space) as an AutoText entry. First though select it and under the Review tab > Language set it to not check spelling or grammar. This is like character formatting.

I have a character style with this attribute that I use for citations in legal briefs.

Then save it as an AutoText entry so you won't have to go through this every time.

As far as I know, there is no other way to turn off grammar rules for just one word.