shrewd implies keenness of mind, sharp insight, and a cleverness in practical matters a shrewd comment, businessman, etc.; sagacious implies keen discernment and farsighted judgment a sagacious counselor; perspicacious suggests the penetrating mental vision or discernment that enables one clearly to see and understand what is obscure, hidden, etc. a perspicacious judge of character; astute implies shrewdness combined with sagacity and sometimes connotes, in addition, artfulness or cunning an astute politician See also syn. study at clever.
These adjectives mean having or showing keen awareness, sound judgment, and often resourcefulness, especially in practical matters. Shrewd suggests a sharp intelligence, hardheadness, and often an intuitive grasp of practical considerations: “He was too shrewd to go along with them upon a road which could lead only to their overthrow” (J.A. Froude). Sagacious connotes prudence, discernment, and farsightedness: “He was observant and thoughtful, and given to asking sagacious questions” (John Galt). Astute suggests shrewdness, especially with regard to one's own interests: An astute tenant always reads the small print in a lease.Perspicacious implies penetration and clear-sightedness: She is much too perspicacious to be taken in by such a spurious argument.