Not to be accounted for or explained:
— Perceptible only as unaccountable influences that hinder progress.

synonym: unexplainable.

Roget 83: uncomformable, exceptional; abnormal, abnormous^†; anomalous, anomalistic; out of order, out of place, out of keeping, out of tune, out of one's element; irregular, arbitrary; teratogenic; lawless, informal, aberrant, stray, wandering, wanton; peculiar, exclusive, unnatural, eccentric, egregious; out of the beaten track, off the beaten track, out of the common, out of the common run; beyond the pale of, out of the pale of; misplaced; funny.    unusual, unaccustomed, uncustomary, unwonted, uncommon; rare, curious, odd, extraordinary, out of the ordinary; strange, monstrous; wonderful etc. 870; unexpected, unaccountable; outre [Fr.], out of the way, remarkable, noteworthy; queer, quaint, nondescript, none such, sui generis [Lat.]; unfashionable; fantastic, grotesque, bizarre; outlandish, exotic, tombe des nues [Fr.], preternatural; denaturalized^†.    heterogeneous, heteroclite [Gramm.], amorphous, mongrel, amphibious, epicene, half blood, hybrid; androgynous, androgynal^†; asymmetric etc. 243; adelomorphous^†, bisexual, hermaphrodite, monoclinous^†.    qualified etc. 469.    singular, unique, one-of-a-kind.    newfangled, novel, non-classical; original, unconventional, unheard of, unfamiliar; undescribed, unprecedented, unparalleled, unexampled.    ... show more

Roget 519: unintelligible, unaccountable, undecipherable, undiscoverable, unknowable, unfathomable; incognizable^†, inexplicable, inscrutable; inapprehensible^†, incomprehensible; insolvable^†, insoluble; impenetrable.    illegible, as Greek to one, unexplained, paradoxical; enigmatic, enigmatical, puzzling (secret) 533; indecipherable.    obscure, dark, muddy, clear as mud, seen through a mist, dim, nebulous, shrouded in mystery; opaque, dense; undiscernible etc. (invisible) 447^†; misty etc. (opaque) 426; hidden etc. 528; latent etc. 526.    indefinite, garbled etc. (indistinct) 447; perplexed etc. (confused) 59; undetermined, vague, loose, ambiguous; mysterious; mystic, mystical; acroamatic^†, acroamatical^†; metempirical; transcendental; occult, recondite, abstruse, crabbed.    inconceivable, inconceptible^†; searchless^†; above comprehension, beyond comprehension, past comprehension; beyond one's depth; unconceived.    inexpressible, undefinable, incommunicable.    unpredictable, unforeseeable.    ... show more

Roget 927a: exempt, free, immune, at liberty, scot-free; released etc. v.; unbound, unencumbered; irresponsible, unaccountable, not answerable; excusable.    ... show more

Roget 964: illegal [contrary to law], unlawful, illegitimate; not allowed, prohibited etc. 761; illicit, contraband; actionable.    unwarranted, unwarrantable; unauthorized; informal, unofficial; injudicial^†, extrajudicial.    lawless, arbitrary; despotic, despotical^†; corrupt, summary, irresponsible; unanswerable, unaccountable.    [of invalid or expired law] expired, invalid; unchartered, unconstitutional; null and void; a dead letter.    [in absence of law] lawless, unregulated ... show more

Free from control or responsibility.