adjective

(of something bad or unpleasant) utter; complete (used for emphasis).

it’s a downright disgrace

complete,total,absolute,utter,thorough,perfect,out-and-out,outright,thoroughgoing,all-out,sheer,positive,rank,pure,dyed-in-the-wool,deep-dyed,real,veritable,consummate,categorical,unmitigated,unqualified,unadulterated,unalloyed,unconditional,unequivocal,right,proper,arrant

adverb

to an extreme degree; thoroughly.

he was downright rude

thoroughly,utterly,positively,simply,profoundly,really,absolutely,completely,totally,entirely,perfectly,properly,consummately,surpassingly,unconditionally,unreservedly,categorically,incontrovertibly,unquestionably,undeniably,in every respect,through and through,outright,plain,clean