godan verb (-ru), intransitive verb
be obvious; be clear; be completely understood
Expresses that something is so evident it needs no explanation, or that one understands something fully. Often used in the form わかりきっている or わかりきったこと.
そんなことはわかりきっている。
That's obvious.
彼が嘘をついているのはわかりきったことだ。
It was clear that he was lying.