WordNet: epäselvä, hämärä, vaikeaselkoinen

not clearly understood or expressed; "an obscure turn of phrase"; "an impulse to go off and fight certain obscure battles of his own spirit"-Anatole Broyard"; "their descriptions of human behavior become vague, dull, and unclear"- P.A.Sorokin"; "vague...forms of speech...have so long passed for mysteries of science"- John Locke"