I just finally learned 伏せる on WaniKani and I was a bit surprised.
While WaniKani gives to cover/to hide (1) and to turn over (2) as the two primary meanings, in Novels I usually see 伏せる as somebody turning down their eyes/tilting down their head/view downwards, this meaning is also reflected in the Jitendex dictionary. Now I do wonder, why is the meaning not taught on WaniKani, is it too rare or are the other meanings really more important? For me it seems like it´s kinda the opposite.
I’m definitely more familiar with the “conceal/hide” meaning myself. Maybe you read an author who loved to use this verb in the meaning you mention? Most authors have pet words/expressions they use a lot more than average.
It may be the case that one novel I recently read used it more often than usual, but I do think especially 目を伏せる as an expression is quite common. 目を伏せる has a (relatively) high frequency according to the dictionary/Innocent Corpus and NINJAL-LWP. So I do think it would make sense to at least include it as a meaning in addition to the other ones.
Well yeah but isn’t that literally just “to conceal one’s eyes”? I feel like it’s an extension of the core meaning.
I think all the definitions you mentioned are roughly equal in frequency, but Wanikani doesn’t want to overload people with many definitions, so it chooses the most general of them. In this case, “to cover/to hide” nearly encapsulates the idea of “turning down one’s eyes” as a type of “covering” or “hiding” action, so if you happened to encounter that definition in the wild, you’ll be like “Oh, I remember this other definition for this word meaning ‘to cover/to hide’ and this new definition I learned is somewhat similar to it.” And so it would be easier to stick.