>>16009620It's literally "mountain" + "man", and refers to "a man that does stuff up in the mountains" in general, whether it be hiking, climbing, hunting, trapping, lumbering... it's pretty broad. Considering they, quote Bulbapedia themselves, "appear as large, bearded men carrying a walking stick and hiking gear", it's pretty clear they're supposed to be hikers.
The entire "mountaineer" shit is just some kid who knows やま means mountain and おとこ means man thinking he knows better than the actual translators.
Bulbapedia has a tendency to suffer from this in general. Lots of their "more accurate translations" of terms are actually less accurate because they don't fully understand what words mean.
