adjective

having or showing a composed or serious manner that is worthy of respect.

she maintained a dignified silence

stately,noble,courtly,majestic,kingly,distinguished,proud,august,lofty,exalted,regal,lordly,imposing,impressive,grand,solemn,serious,grave,formal,proper,ceremonious,decorous,reserved,composed,sedate,staid,couth,just so,starchy