Because the hiragana ends with an う sound, you know this word is a verb. The kanji itself means lean, and the verb vocab version means to be leaned or to be tilted. You aren't doing the leaning or the tilting, though, you're just watching, which is why you say "cool" (く) when you see it, because it's already done.

You cut a moo (かたむ), that is, a cow, in half. Then you request it is leaned up against the fence so you can start harvesting its meat for sustenance.