acuity

depth; deepness; profundity, depression (concavity)., hollow, pit, shaft, well, crater; gulf; bowels of the earth, botttomless pit, hell., soundings, depth of water, water, draught, submersion; plummet, sound, probe; sounding rod, sounding line; lead.

be deep; render deep; deepen., plunge; sound, heave the lead, take soundings; dig (excavate).

deep, deep seated; profound, sunk, burried; submerged; subaqueous, submarine, subterranean, subterrene; underground., bottomless, soundless, fathomless; unfathomed, unfathomable; abysmal; deep as a well; bathycolpian; benthal, benthopelagic; downreaching, yawning., knee deep, ankle deep.

beyond one's depth, out of one's depth; over head and ears.

intelligence, capacity, comprehension, understanding; cuteness, sabe [U.S.], savvy [U.S.]; intellect; nous, parts, sagacity, mother wit, wit, esprit, gumption, quick parts, grasp of intellect; acuteness; acumen, subtlety, penetration, perspicacy, perspicacity; discernment, due sense of, good judgment; discrimination; cunning; refinement (taste)., head, brains, headpiece, upper story, long head; eagle eye, eagle glance; eye of a lynx, eye of a hawk., wisdom, sapience, sense; good sense, common sense, horse sense [U.S.], plain sense; rationality, reason; reasonableness; judgment; solidity, depth, profundity, caliber; enlarged views; reach of thought, compass of thought; enlargement of mind., genius, inspiration, geist, fire of genius, heaven-born genius, soul; talent (aptitude)., [Wisdom in action] prudence [more]; vigilance; tact; foresight; sobriety, self-possession, aplomb, ballast., a bright thought, not a bad idea.

be intelligent; have all one's wits about one; understand (intelligible); catch an idea, take in an idea; take a joke, take a hint., see through, see at a glance, see with half an eye, see far into, see through a millstone; penetrate; discern (descry); foresee., discriminate; know what's what [more]; listen to reason.

[Applied to persons] intelligent, quick of apprehension, keen, acute, alive, brainy, awake, bright, quick, sharp; quick witted, keen witted, clear witted, sharp-eyed, sharp sighted, sharp witted; wide-awake; canny, shrewd, astute; clear-headed; farsighted; discerning, perspicacious, penetrating, piercing; argute; nimble-witted, needle-witted; sharp as a needle; alive to (cognizant); clever (apt); arch (cunning); pas si bete; acute., wise, sage, sapient, sagacious, reasonable, rational, sound, in one's right mind, sensible, abnormis sapiens, judicious, strong-minded., unprejudiced, unbiased, unbigoted, unprepossessed; undazzled, unperplexed; of unwarped judgment, impartial, equitable, fair., cool; cool-headed, long-headed, hardheaded, strong-headed; long-sighted, calculating, thoughtful, reflecting; solid, deep, profound.