Klein Dictionary, סתם 1

סתם to stop up, close; to express oneself vaguely.
    — Qal - סָתַם 1 he stopped up, closed; PBH 2 he expressed himself vaguely.
    — Niph. - נִסְתַּם 1 was stopped up, was closed (in the Bible occurring only Neh. 4:1); PBH 2 was concealed with force.
    — Pi. - סִתֵּם he stopped up or closed (in the Bible occurring only Gen. 26:15 and 18).
    — Nith. - נִסְתַּתֵּם 1 was stopped up, was closed; 2 ceased. [Aram. סֽתַם (= he stopped up, closed), Syr. סֽטַם (= he closed, bound, restrained, stopped, closed), Arab. saṭama (= he closed the door). cp. Akka. shutummu (= storehouse). cp. also שׂתם, שׁתם, and the second element in שַׁסְתּוֹם.] Derivatives: סֶתֶם, סְתָם, סָתוּם, סִתּוּם, הִסְתַּתּֽמוּת, מַסֽתֵּם. cp. שַׁסְתּוֹם.