Caustic indicates the corroding effect of some strong chemical, as nitrate of silver. We say a sour face, sharp words, bitter complaints, caustic wit, cutting irony, biting sarcasm, a stinging taunt, harsh judgment, a tart reply.

J. C. Fernald, English Synonyms and Antonyms (1914)

Example sentences

bitter The wronged parties couldn't help but feel bitter.
corrosive The cheapest of nepenthes are often the most corrosive.
acrid There's an acrid smell here. Is something burning?
sarcastic I wonder whether Tom and Mary are being sarcastic.

Popularity over time

Word	1850 → 2019	Trend
caustic		falling
bitter		steady
corrosive		falling
acrid		rising
mordant		falling
sarcastic		rising

Use in printed books, per decade from 1850 to 2019.

By length

4 letters: acid², keen¹, sour², tart¹
5 letters: sharp¹, nasty², harsh¹, catty², acrid², acerb
6 letters: severe², bitter², biting², acidic³, bitchy²
7 letters: cutting², burning², searing², pungent², acerbic³, mordant², piquant², erosive³
8 letters: piercing², poignant², stinging², scathing², virulent³, spiteful², incisive³
9 letters: malicious³, sarcastic³, satirical⁴, corrosive³, vitriolic⁴, trenchant², truculent³, sulfurous
10 letters: irritating⁴, blistering³, sulphurous, mordacious, escharotic
11 letters: destructive³, penetrating⁴, acrimonious⁵

The small number after each word is its number of syllables (acid² = 2 syllables).