I. (v.) glatigar (hair, clothes, etc.) (level) planigar (earth, etc.);

(polish) polisar;
(to make easy, to free) faciligar (ulo ad ulu);
(the brow) senrugigar;
(calm) pludolcigar, dolcigar, kalmigar (cf. flatar; karezar).
smooth out - glatigar, platigar, solvar
smooth over - aranjar

II. (adj.) glata; plana;

(bland) dolca;
(sea) kalma.
smooth-faced - senbarba; (fig.) hipokrito (cf. Tartufo).