A limit or boundary—the maximum point or extent that cannot be exceeded (in ability, capacity, tolerance, etc.).
彼は体力の限界を感じて競技をやめた。
He felt he had reached his physical limit and quit the competition.
この機械の処理能力には限界がある。
This machine has a limit to its processing capability.
私たちの忍耐も限界だ。
Our patience has its limits.