Synonyms for Caustic:

adj.

burning, corrosive (adjective)
alkaline, pungent, erosive, acrid, tart, keen, acid, acerbic, astringent.
irritable (adjective)
huffy, tart, bearish, crusty, acrimonious, acid, bitter, petty, cross, irritable, sour, cranky, snappish, touchy, cantankerous, petulant, peevish, crabbed, spiteful, acerbic, irascible, surly, bellicose, churlish, prickly.
pungent (adjective)
spicy, sharp, bitter, pungent, sour, piquant, poignant, acrid, tangy.
sarcastic (adjective)
bitter, sharp, trenchant, acrimonious, severe, scathing, cutting, harsh, acerb, virulent.
severe (adjective)
basic, gruff, disciplined, puritanical, chilly, abrupt, severe, keen, fundamental, demanding, curt, cool, cutting, icy, sharp, censorious, dour, dry, acrimonious, raw, rigorous, acerbic, draconian, astringent, acute, correct, stark, spare, frosty, brisk, crisp, strict, short, unbending, obdurate, hidebound, harsh, grim, prudish, inflexible, intense, stiff-necked, piquant, brusque, exacting, rigid, strait-laced, uncompromising, obstinate, tart, lean, spartan, ascetic, intolerant, austere, oppressive, stern, relentless, imperial, authoritarian, critical, blunt, bleak, stringent, meticulous, precise.
sharp (adjective)
sharp.

n.

accusatory, ad hominem, accusing. attack, slashing, trenchant, mordacious, truculent, scathing, respect. caustic (noun)
corrosive, erosive, bitter, destructive, venomous, blistering, vitriolic, acerbic, sulphurous, acrid, virulent, acerb, acid, sulfurous, unpleasant.
corrosive (noun)
burning, alkaline.
sarcastic (noun)
scathing, sarcastic.

Other synonyms:

mordacious. scathing, trenchant, slashing. truculent. alkali
alkaline.
scornful
sarcastic.
Other relevant words:
destructive, sarcastic, blistering, venomous, mordacious, slashing, acrid, attack, erosive, sulfurous, scathing, sulphurous, vitriolic, virulent, corrosive, acerb, truculent, respect, burning, unpleasant, alkaline, accusatory, trenchant, accusing.

Usage examples for caustic

  1. " Strange is very caustic – The Obstacle Race by Ethel M. Dell
  2. For snake bite, or the bite of a dog, tie a string above the bite, wash the wound with clean water, and rub carbolic acid or luna caustic on it. – Keep-Well Stories for Little Folks by May Farinholt-Jones
  3. While he thought of caustic remarks, with which to greet such a person, he saw the head of a horse push up into view over the edge of the hill. – Hopalong Cassidy by Clarence E. Mulford