Although I had stabbed my mom with a knife, I slept soundly that night.
Because the hiragana ends with an う sound, you know this word is a verb. The kanji itself means stab so the verb vocab version is to stab.
If you're going to stab someone, use a saw (さ). It may seem more difficult to stab them with a saw at first, but when you see the damage, plus how hard it is to get back out, you'll realize a saw is the ideal stabbing tool.