re·gres·sion /rɪˈɡreʃən/ noun [countableC, uncountableU] 1. the act of returning to an earlier condition that is worse or less developed 退步,倒退;退化 OPP progression
2. technical the act of thinking or behaving as you did at an earlier time of your life, such as when you were a child 〔思想或行为的〕退化;退行