To teach their son responsibility, they used tough-love by making him earn his own pocket money.

tough 的意思是"强硬的、严厉的"，表示采取严格或坚决的态度。 love 的意思是"爱"，指对某人深切的情感关怀。 tough-love 是一个复合词，指"严厉的爱"或"强硬的爱"，这种教育方式表面上看似严厉，但目的是为了帮助对方成长和培养责任感。