re·sid·u·al /rɪˈzɪdʒuəl/ ●○○ adjectiveadj [only before noun] formalREMAIN/BE LEFT remaining after a process, event etc is finished 残余的,剩余的 the residual effects of drug treatment 药物治疗的残留作用
residual income (=the money left from what you earn after you have paid your taxes) 税后收入