As with any word, you're aware of roughly how often you've heard it or read it, so can gauge how unfamiliar it will be to your audience. Here you can use any word, but to most audiences politeness demands you use words they'll probably understand.

Understanding doesn't require that the hearer has heard it before. Anyone can work out gruntled if you're using it for humorous effect, though the famous Wodehouse quote does take the precaution of using the original word as well: I can't remember how it goes exactly, something like Jeeves was, if not exactly disgruntled, far from gruntled.

Tinguished is wrong in any case, if we're taking this seriously: both distinguish and extinguish are from the Latin stinguo, meaning 'prick, mark off' in one case and 'extinguish, quell' in the other. (A bit puzzling that, but Lewis & Short seem to think they're the same.)