Very difficult to bear or endure; unbearable or intolerable (pain, hardship, feeling).
耐え難い痛みに襲われて、救急車を呼んだ。
I was struck by unbearable pain and called an ambulance.
彼の裏切りは耐え難いものだった。
His betrayal was intolerable.
暑さが耐え難くなり、窓を開けた。
The heat became unbearable, so I opened the window.