秘密的恶习
a bad habit that someone keeps hidden from others
向他人隐瞒的不良习惯
有恶习
to possess a particular bad habit
指有某种特定的不良习惯
沉溺于恶习
to become involved in a bad habit as a source of pleasure
作为一种乐趣，参与到不良习惯中
放纵恶习
to allow oneself to enjoy a particular bad habit
放任自己享受某种不良习惯