retrogression

n [U] return to a less advanced state; decline 退步; 退化; 衰退; 衰落.

retractile, retraction, retread, retreat, retrench, retrenchment, retrial, retribution, retributive, retrievable, retrieval, retrieve, retriever, retro-, retro-rocket, retroactive, retroactively, retroflex, retrograde, retrogress, retrogressive, retrogressively, retrospect, retrospection, retrospective, retrospectively, retrousse, retry, retsina, return, return address, return fare, return game, return match, return ticket, return to..., returnable, returnee, returning officer, reunion, reunite,