Synonyms for Clear as mud:

• adj.

  •equivocal (adjective)
  • clouded,
  • misleading,
  • hazy,
  • questionable,
  • unintelligible,
  • oblique,
  • suspect,
  • ambiguous,
  • unexplicit,
  • undecided,
  • indistinct,
  • indefinite,
  • puzzling,
  • indeterminate,
  • muzzy,
  • borderline,
  • evasive,
  • problematic,
  • disreputable,
  • tenebrous,
  • fuzzy,
  • suspicious,
  • Amphibological,
  • vague,
  • ambivalent,
  • dubious,
  • muddled,
  • unclear,
  • fishy,
  • with mixed feelings,
  • open.
  •uncomprehensible (adjective)
  • un-comprehensible,
  • un comprehensible.
  •unfathomable (adjective)
  • indecipherable,
  • profound,
  • too deep,
  • uncomprehensible,
  • heavy.

• Other synonyms:

  •adj.
  • equivocal,
  • incomprehensible,
  • obscure,
  • unfathomable.
  •n.
  • shadowy.
  •Other relevant words:
  • abysmal,
  • abyssal,
  • addled,
  • afford,
  • apart,
  • arduous,
  • assailable,
  • backbreaking,
  • bass,
  • becloud,
  • become flat,
  • bedim,
  • befog,
  • befuddled,
  • benighted,
  • big,
  • black,
  • bleak,
  • bleary,
  • blind,
  • blue,
  • blur,
  • blurred,
  • blurry,
  • boggy,
  • border,
  • boundary line,
  • break,
  • break down,
  • brumous,
  • buy the farm,
  • byzantine,
  • cabalistic,
  • candid,
  • capable,
  • choke,
  • clayey,
  • clear,
  • cloggy,
  • cloud,
  • cloud-covered,
  • cloudy,
  • complex,
  • confuse,
  • confused,
  • conk,
  • conk out,
  • convoluted,
  • croak,
  • cryptical,
  • darkness,
  • debatable,
  • decease,
  • deceptive,
  • deeply,
  • defendant,
  • delimitation,
  • delphian,
  • dense,
  • devious,
  • dice,
  • die out,
  • dimmed,
  • dingy,
  • dip,
  • dirty,
  • disconnected,
  • disconsolate,
  • disjointed,
  • dismal,
  • disordered,
  • distrust,
  • divinatory,
  • dour,
  • drab,
  • drear,
  • dreary,
  • dubitable,
  • dull,
  • dumb,
  • eclipse,
  • elusive,
  • enceinte,
  • exit,
  • expectant,
  • expire,
  • exposed,
  • fail,
  • faint,
  • fizzing,
  • fleshy,
  • fog,
  • foggy,
  • formless,
  • fundamental,
  • funny,
  • fuzzed,
  • garbled,
  • give,
  • give out,
  • give way,
  • gloomy,
  • glowering,
  • glum,
  • go,
  • go bad,
  • grave,
  • gravid,
  • great,
  • grecian,
  • grievous,
  • grim,
  • grueling,
  • gruelling,
  • hard,
  • haze over,
  • heavily,
  • hellene,
  • hellenic,
  • hide,
  • ill-defined,
  • impossible,
  • improbable,
  • in question,
  • incognoscible,
  • indissoluble,
  • intemperate,
  • isolated,
  • kick the bucket,
  • kinky,
  • knotty,
  • labored,
  • laborious,
  • laboured,
  • large,
  • late,
  • leaden,
  • leery,
  • loose,
  • lowering,
  • lumbering,
  • mantic,
  • marginal,
  • marshy,
  • mired,
  • mirky,
  • miry,
  • mist,
  • mistrust,
  • mistrustful,
  • moody,
  • morose,
  • mucky,
  • muddied,
  • muddy up,
  • murky,
  • mystic,
  • mystical,
  • night,
  • nighttime,
  • oblique case,
  • obliterate,
  • obtuse,
  • oceanic abyss,
  • offbeat,
  • on the fence,
  • open up,
  • opened,
  • oracular,
  • orphic,
  • out of sight,
  • out of the question,
  • outdoors,
  • overcast,
  • overcloud,
  • overt,
  • overweight,
  • pall,
  • pass,
  • pass away,
  • perish,
  • ponderous,
  • pop off,
  • problematical,
  • punishing,
  • quaggy,
  • quirky,
  • receptive,
  • refutable,
  • rich,
  • saturnine,
  • scattered,
  • secret,
  • shadow,
  • shadowed,
  • shady,
  • shapeless,
  • sibyllic,
  • sinister,
  • sloppy,
  • sloughy,
  • slow,
  • slur,
  • snuff it,
  • soggy,
  • sonorous,
  • sorry,
  • sound,
  • sour,
  • spread,
  • squashy,
  • subdued,
  • subject,
  • sullen,
  • sunless,
  • supernatural,
  • surface,
  • surmise,
  • swampy,
  • tangled,
  • tenebrific,
  • tenebrious,
  • tentative,
  • thick,
  • threatening,
  • toilsome,
  • tortuous,
  • tough,
  • trench,
  • turbid,
  • umbrageous,
  • unconnected,
  • unconvincing,
  • uncrystallised,
  • uncrystallized,
  • undecipherable,
  • undefendable,
  • undefended,
  • undetermined,
  • unexplainable,
  • unfastened,
  • unfathomed,
  • unfold,
  • unknown,
  • unlikely,
  • unlogical,
  • unnoticeable,
  • unplumbed,
  • unreadable,
  • unresolved,
  • unsounded,
  • unstructured,
  • unsung,
  • untrusting,
  • vatic,
  • vatical,
  • veil,
  • wakeless,
  • wary,
  • waterlogged,
  • weighed down,
  • weighty,
  • wickedness,
  • wispy,
  • with child,
  • woolly,
  • woolly-headed,
  • wooly,
  • wooly-minded,
  • wraithlike,
  • occult arts,
  • external oblique muscle,
  • musculus obliquus externus abdominis,
  • abdominal external oblique muscle,
  • heart-to-heart,
  • open air,
  • blot out,
  • cash in one's chips,
  • give-up the ghost,
  • confutable,
  • confutative,
  • kabbalistic,
  • qabalistic,
  • out-of-doors,
  • spread out,
  • way-out,
  • drop dead.

Antonyms for Clear as mud:

• adj.

  • equivocal
    certain, definite, obvious, plain, unequivocal, unquestionable, determined, clear, sure.
  • incomprehensible
    comprehensible, understandable, believable, fathomable, imaginable, intelligible.
  • obscure
    bright, famous, distinguished, bare, public, common, visible, known, straightforward, apparent, exposed, perceptible, unmysterious, explicit, open, understood, uncovered.
  • unfathomable
    explicable, explainable.