stol·id (stŏl'ĭd) adj.
stol·id·er, stol·id·est Having or revealing little emotion or sensibility; impassive: "the incredibly massive and stolid bureaucracy of the Soviet system"(John Kenneth Galbraith).
[Latin stolidus, stupid; see stel- in Indo-European roots.] sto·lid'i·ty (stŏ-lĭd'ĭ-tē, stə-), stol'id·ness (stŏl'ĭd-nĭs) n., stol'id·ly adv.
1563 (implied in stolidity), from M.Fr. stolide (16c.), from L. stolidus "insensible, dull, brutish," prop. "unmovable," related to stultus "foolish," from PIE base *stel- "to cause to stand, to place," from base *sta- (see stet).