lucid
     adj 1: (of language) transparently clear; easily understandable;
            "writes in a limpid style"; "lucid directions"; "a
            luculent oration"- Robert Burton; "pellucid prose"; "a
            crystal clear explanation"; "a perspicuous argument"
            [syn: {limpid}, {luculent}, {pellucid}, {crystal clear},
             {perspicuous}]
     2: having a clear mind; "a lucid moment in his madness"
     3: capable of thinking and expressing yourself in a clear and
        consistent manner; "a lucid thinker"; "she was more
        coherent than she had been just after the accident" [syn:
        {coherent}, {logical}]
     4: transmitting light; able to be seen through with clarity;
        "the cold crystalline water of melted snow"; "crystal
        clear skies"; "could see the sand on the bottom of the
        limpid pool"; "lucid air"; "a pellucid brook";
        "transparent cristal" [syn: {crystalline}, {crystal clear},
         {limpid}, {pellucid}, {transparent}]
Source: WordNet® 2.0