inexpressive
adjective
apathetic, blank, characterless, cold, deadpan, devoid of expression, dim, dull, empty, enigmatic, enigmatical, expressionless, hardened, impassive, impenetrable, imperturbable, impervious, incomprehensible, inexplicable, inscrutable, lackluster, listless, meaningless, nebulous, nonsensical, obtuse, poker-faced, puzzling, senseless, spiritless, stupid, trite, unaffected, unanimated, undecipherable, unemotional, unfathomable, unintelligible, unmoved, vacant, vacuous, vague, void
Burton's Legal Thesaurus.
William C. Burton.
2006