undeniable, a. incontestable, indisputable, unquestionable, indubitable, irrefragable, incontrovertible, unimpeachable.

under, prep. beneath, below, subordinate, inferior, subject to.

under, a. subordinate, subaltern, inferior, subjacent.

underbrush, n. undergrowth, jungle.

underground, a. subterranean, subterraneous, subterrene, subterrestrial.

underhand, a. underhanded, surreptitious, clandestine, covert.

underhand, adv. clandestinely, covertly, secretly, surreptitiously.

underhanded, a. covert, clandestine, surreptitious, underhand.

underline, v. underscore.

underling, n. subordinate, inferior, understrapper.

underlying, a. fundamental, basic.

underrate, v. underestimate, undervalue, underprize.

understand, v. comprehend, apprehend, grasp, discern.

understandable, a. comprehensible, intelligible.

understanding, n. comprehension, discernment, apprehension; accord, entente, harmony, agreement.  Associated Word:  tacit.

under the rose. secretly, privately, confidentially, sub rosa.

undervalue, v. depreciate, vilipend, despise; underrate, underestimate.

under water. submarine, subaquatic, subaqueous, submerged.

underwear, n. underclothing; lingerie.

underwrite, v. insure; subscribe.

undeserved, a. unmerited, unjust.

undeserving, a. unworthy, unmeritorious, indign.

undesigned, a. unpremeditated, unintentional, accidental.

undesigning, a. artless, guileless, sincere.

undesirable, a. inexpedient; objectionable, unacceptable, ineligible.

undetermined, a. unsettled, irresolute, wavering, indeterminate, abeyant.

undeveloped, a. in embryo, embryonic, immature, abeyant, embryo, imperfect; atrophied, dwarfed, rudimentary, stunted, abortive, puny.

undevelopment, n. immaturity; atrophy, abortion; embryo.

undignified, a. unseemly, unbecoming, groveling, servile, obsequious.

undiminished, a. unabated, unlessened.

undiscernible, a. imperceptible, indiscernible.

undisputable, a. incontrovertible, incontestable, indisputable, undeniable.

undissolvable, a. insoluble, indissolvable, indissoluble.

undo, v. reverse, annul, nullify, abrogate, neutralize, invalidate; loose, unfasten, disentangle; impoverish, ruin.

undoing, n. reversal, annulment, invalidation, abrogation; impoverishment, ruin.

undoubted, a. indubitable, unquestioned, unchallenged, undisputed.

undoubting, a. sure, confident, sanguine, implicit.

undress, n. dishabille, negligee.

undress, v. disrobe, strip, divest, doff, disarray.

undressing, n. disrobing, stripping.

undue, v. unreasonable, immoderate, exorbitant, excessive, disproportioned.