piercing
1 (usually of sound) ear-splitting, high-pitched, loud, penetrating, sharp, shattering, shrill
2 alert, aware, bright (informal) keen, penetrating, perceptive, perspicacious, probing, quick-witted, searching, sharp, shrewd
3 (usually of weather) arctic, biting, bitter, cold, freezing, frosty, keen, nipping, nippy, numbing, raw, wintry
4 acute, agonizing, excruciating, exquisite, fierce, intense, painful, powerful, racking, severe, sharp, shooting, stabbing
Antonyms
1 inaudible, low, low-pitched, mellifluous, quiet, soundless
2 obtuse, slow, slow-witted, thick, unperceptive