degressive
/dɪˈgresɪv/adjective
1- reducing by gradual amounts递减的。
1.1
- (of taxation) at successively lower rates on lower amounts（税收）税率递减的。
词源
late 19th cent.: from Latin degress-'descended' （from the verb degredi, from de-'down' + gradi 'walk'） + -IVE.