None of those stand out as "WTF does that even mean", but maybe I'm the weird one if we adjust for age-demographics or book-reading.
If I had to guess at a riskier 20%... Guava, a fruit some people may not have had; Gunky because it's slang; Mogul, Vogue, and Mooch were borrowed from other languages; Cello is something people may have heard more than read; Hoist.
Even as someone who already knows the definitions of 100% of those words, it'd still be neat to see those definitions, and maybe even some etymologies or other interesting trivia. “Cello” would be a great opportunity for a factoid about the oldest known cello, “guava” would be a great opportunity for a quick recipe using guavas, etc.
> Perhaps the unusual outcomes are just more memorable, and so seem more frequent?
That's a good point and could very well be true. I just know I've played plenty of games where I was mad that they didn't show the meaning. So let's say its 5% for native speakers, and up to 20% for non-native speakers - that's still a golden opportunity to expand vocabularies. And honestly it can't be a lot of work to add a couple lines of static text. At worst it would be ignored, and at most, help people learn more interesting words.
If I had to guess at a riskier 20%... Guava, a fruit some people may not have had; Gunky because it's slang; Mogul, Vogue, and Mooch were borrowed from other languages; Cello is something people may have heard more than read; Hoist.