The service at this restaurant was totally amateur-hour, with waiters who couldn't even remember the menu.

amateur 来自法语，原意是"爱好者"，指非专业人士从事某项活动。hour 意思是"小时"，这里指"时间段"。 amateur-hour 是俚语表达，字面意思是"业余时间"，引申为"不专业的表现"或"外行行为"，常用来批评服务质量差或表现不专业。