This is the 5569th most frequent Japanese word.
きれる
"きれる" means "to break, snap, or cut; to expire; to lose temper (depending on context)."
In this sentence, '切れる' refers to an object's ability to cut effectively, describing the sharpness or cutting capability of the knife.
このナイフは鋭くてよく切れる。
This knife is sharp and cuts well.
Here, '切れる' metaphorically represents the emotional action of snapping or losing one's temper.
彼は怒るとすぐに切れる人です。
He is someone who quickly snaps when angry.
In this context, '切れる' signifies that something (electricity) has stopped or been disconnected/unavailable.