Roget's Thesaurus of English Words and Phrases by Peter Mark Roget

never be; sour grapes; hopelessness &c 859. V. be impossible &c adj.; have no chance whatever. attempt impossibilities; square the circle, wash a blackamoor white; skin a flint; make a silk purse out of a sow's ear, make bricks without straw; have nothing to go upon; weave a rope of sand, build castles in the air, prendre la lune avec les dents [Fr.], extract sunbeams from cucumbers, set the Thames on fire, milk a he-goat into a sieve, catch a weasel asleep, rompre l'anguille au genou [Fr.], be in two places at once. Adj. impossible; not possible &c 470; absurd, contrary to reason; unlikely; unreasonable &c 477; incredible &c 485; beyond the bounds of reason, beyond the bounds of possibility, beyond the realm of possibility; from which reason recoils; visionary; inconceivable &c (improbable) 473; prodigious &c (wonderful) 870; unimaginable, inimaginable†; unthinkable. impracticable unachievable; unfeasible, infeasible; insuperable; unsurmountable†, insurmountable; unattainable, unobtainable; out of reach, out of the question; not to be had, not to be thought of; beyond control; desperate &c (hopeless) 859; incompatible &c 24; inaccessible, uncomeatable†, impassable, impervious, innavigable†, inextricable; self- contradictory. out of one's power, beyond one's power, beyond one's depth, beyond one's reach, beyond one's grasp; too much for; ultra crepidam [Lat.]. Phr. the grapes are sour; non possumus [Lat.]; non nostrum tantas componere lites [Lat.] [Vergil]; look for a needle in a haystack, chercher une aiguille dans une botte de foin [Fr.]; il a le mer à boire†.