| Main Entry: | |
| Part of Speech: | adjective |
| Definition: | mysterious, obscure |
| Synonyms: | abstruse, academic, acroamatic, arcane, cabalistic, concealed, cryptic, dark, deep, difficult, esoteric, hard, heavy*, hermetic, hidden, involved, little-known, mystic, mystical, occult, orphic, pedantic, profound, scholarly, secret |
| Antonyms: | obvious, plain, simple, straightforward |
| Main Entry: | solitary |
| Part of Speech: | adjective |
| Definition: | alone, single; unsociable |
| Synonyms: | aloof, antisocial, cloistered, companionless, deserted, desolate, distant, eremetic, forsaken, friendless, hermitical, hidden, individual, introverted, isolated, lone, lonely, lonesome, lorn, misanthropic, offish, only, out-of-the-way, particular, reclusive, remote, reserved, retired, secluded, separate, sequestered, singular, sole, solo, stag, standoffish, unaccompanied, unapproachable, unattended, uncompanionable, unfrequented, unique, unsocial, withdrawn |
| Antonyms: | accompanied, combined, sociable, together |
| Main Entry: | subconscious |
| Part of Speech: | adjective |
| Definition: | innermost in thought |
| Synonyms: | hidden, inmost, inner, intuitive, latent, mental, repressed, subliminal, suppressed, unconscious |
| Antonyms: | conscious, outer |
| Main Entry: | supernatural |
| Part of Speech: | adjective |
| Definition: | mysterious, not of this world |
| Synonyms: | abnormal, celestial, concealed, dark, fabulous, fairy, ghostly, heavenly, hidden, impenetrable, invisible, legendary, metaphysical, miraculous, mystic, mythical, mythological, numinous, obscure, occult, paranormal, phantom, phenomenal, preternatural, psychic, rare, secret, spectral, superhuman, superior, supermundane, superordinary, supranatural, transcendental, uncanny, uncomprehensible, unearthly, unfathomable, unintelligible, unknowable, unknown, unnatural, unrevealed, unusual |
| Antonyms: | earthly, existent, genuine, natural, real, true |
| Main Entry: | surreptitious |
| Part of Speech: | adjective |
| Definition: | sneaky, secret |
| Synonyms: | clandestine, covert, fraudulent, furtive, hidden, hole-and-corner, hush-hush, on the QT, on the sly, private, skulking, slinking, sly, sneaking, stealthy, sub-rosa, unauthorized, under wraps, under-the-table, undercover, underhand, veiled |
| Antonyms: | aboveboard, authorized, honest, open |
| Main Entry: | ulterior |
| Part of Speech: | adjective |
| Definition: | secret; pertaining to a hidden goal |
| Synonyms: | ambiguous, buried, concealed, covert, cryptic, dark, enigmatic, equivocal, guarded, hidden, implied, obscure, obscured, personal, privy, remote, secondary, selfish, shrouded, under cover, under wraps, undisclosed, undivulged, unexpressed, unsaid |
| Antonyms: | expressed, known, overt, public |
| Main Entry: | uncharted |
| Part of Speech: | adjective |
| Definition: | unknown |
| Synonyms: | alien, concealed, distant, exotic, far-off, faraway, foreign, hidden, little known, remote, undiscovered, unexplored, unheard-of, unidentified, unmapped, unnamed |
| Main Entry: | undercover |
| Part of Speech: | adjective |
| Definition: | secret, spy |
| Synonyms: | clandestine, concealed, confidential, covert, creep, furtive, hidden, hole-and-corner, hush-hush, incognito*, intelligence, on the QT, private, stealth, stealthy, sub-rosa, surreptitious, under wraps, underground, underhand, underneath |
| Antonyms: | known, open, public |
| Main Entry: | underground |
| Part of Speech: | adjective |
| Definition: | secret, subversive |
| Synonyms: | alternative, avant-garde, clandestine, concealed, covert, experimental, hidden, hush-hush, on the QT, on the sly, private, radical, resistant, resistive, revolutionary, surreptitious, unbowed, unconventional, under wraps, undercover, unusual |
| Antonyms: | authorized, condoned, known, legal, public |