senior moment
noun [ C, usually singular ] informal uk/ˌsiː.ni.ə ˈməʊ.mənt/ us/ˌsiː.njɚ ˈmoʊ.mənt/
老痴瞬间（指上了年纪的人偶发的健忘现象）
an occasion when someone forgets something in a way that is thought to be typical of older people
Is this just a senior moment or am I losing my memory? 这到底是老痴瞬间还是我失忆了？
I always write important names down, in case I have a senior moment. 我总是把重要的名字写下来，以防老痴瞬间。