Retrogressive describes a thing that moves toward an earlier, worse state — a law that takes rights away, a school plan that undoes a careful reform, an attitude that pulls a group back into harsher habits. It is an adjective with a clear frown in it. Though actually, students often meet a lookalike first: retrospective, which is about looking at the past, not becoming the past. A retrospective show of paintings is a look back; a retrogressive policy is a step down. In science you may also see it for living things that have become simpler. In everyday talk, people are more likely to say backward-looking or a step backwards.

倒退的；退化的