Rare, imperspicuous; puzzling, baffling, enigmatic, enigmatical; mysterious, arcane, inexplicable, unexplainable, insolvable, insoluble, unaccountable, inextricable.
undefended, adj. 1. defenseless, unprotected, unguarded, unsheltered; unfortified, unarmed, weaponless, weak, helpless, powerless, impotent; insecure, unsafe, dangerous, perilous, precarious.
2. vulnerable, expugnable, uncovered, exposed, naked, wide open; open to attack, pregnable, penetrable, invadable, attackable, assaultable, assailable.
undefiled, adj. 1. pure, clean, clear, fair, white, immaculate, snowy; stainless, spotless, unspotted, unsmirched, unbesmirched; unsullied, unsoiled, unpolluted, unblemished, unblotted, unstained; untainted, uncorrupted, undistorted, unmarred; uninfected, germ-free, sterilized, sterile, antiseptic, disinfected; fresh, fit to drink or eat, drinkable, eatable, potable, edible; healthful, uninjurious, wholesome, sanitary, innocuous.
2. guiltless, innocent, uncorrupt, clean, moral; virtuous, decent, delicate, proper, seemly; unwanton, undissipated, undissolute, unlicentious; chaste, continent, abstinent, temperate, Rare, intemperate; celibate, virgin, vestal, maidenly, immaculate, intact; impeccable, sinless, above suspicion, inculpable, with clean hands; flawless, faultless.
3. high-principled, upright, righteous, uprighteous; honest, good, sincere; creditable, full of integrity, ethical, high-minded, purehearted, saintly, holy, angelic, divine, godly.
4. unaffected, simple, plain, unornamented, unadorned; tasteful, polished, graceful, refined.
undefined, adj. 1. indefinite, indistinct, impalpable, tenuous; vague, obscure, dim, hazy, nebulous, shadowy, blurred, clouded, veiled; amorphous, formless, shifting, changeable; uncertain, unsure.
2. unexplained, unclear, open to question, unspecified, unspecific, indeterminate, inexact, imprecise; puzzling, perplexing, baffling, mysterious, enigmatic; abstruse, recondite, esoteric, cryptic.
undemonstrative, adj. 1. unresponsive, uncommunicative, unaffectionate, distant, aloof; unexcitable, unemotional, unmoved, unstirred, unperturbed, unsusceptible, unimpressionable, unimpressible; apathetic, phlegmatic, listless, languid; lukewarm, neutral, nonchalant, indifferent; sedate, self-controlled, sober, staid, stoical, philosophical; reserved, shy, demure; calm, composed, poised, quiet, unruffled, placid, stiff, formal, Inf. tight, Sl. uptight.
2. insensitive, unfeeling, uncompassionate, uncaring, heartless; unkind, pitiless, hard-hearted, cold-hearted, marble-hearted, stony-hearted; impervious, stony, steely, flinty; hardened, obdurate, callous, thickskinned; unimpassioned, untouched, indurate, inured.
undeniable, adj. incontestable, indisputable, incon-controvertible, irrefragable, irrefutable, unquestionable, beyond question, admitting of no question or doubt, indubitable, beyond a shadow of a doubt, apodictic; Law. peremptory, inappealable; conclusive, decisive, definite, definitive, solid, fixed, final; impregnable, invincible, unassailable, insuperable, undefeatable, unbeatable; certain, sure, Inf. for-sure, secure, positive; authoritative, unimpeachable, infallible, absolute; proven, demonstrated, established, well-founded.
undependable, adj. 1. unreliable, untrustworthy, untrusty, trustless; irresponsible, fly-by-night, dishonest, disreputable, untruthful; dubitable, doubtful, un-authentic, questionable, disputable, contestable, refutable, unconvincing; uncertain, unassured, inaccurate, implausible, untenable, unbelievable.
