different between heartless vs caustic

English

Etymology

From Middle English hertles, herteles, from Old English heortl?as (“without courage; listless”), equivalent to heart +? -less.

Pronunciation

• (General American) IPA^(key): /?h??t.l?s/
• (Received Pronunciation) IPA^(key): /?h??t.l?s/
• Hyphenation: heart?less

Adjective

heartless (comparative more heartless, superlative most heartless)

1. (obsolete) Without courage; fearful, cowardly. [10th–19th c.]
   • 1782, Frances Burney, Cecilia, II.iii.7:

     Cecilia then, though almost heartless, resolved upon talking with Mr. Harrel himself […].

2. (now rare) Listless, unenthusiastic. [from 14th c.]
3. Without a physical heart. [from 15th c.]
4. Without feeling, emotion, or concern for others; uncaring. [from 16th c.]

   His heartless actions and cold manner left her saddened and feeling alone.

Derived terms

• heartlessly
• heartlessness

Translations

Anagrams

• Earthless, earthless, hartlesse, shearlets

English

Etymology

From the Latin causticus (“burning”), from the Ancient Greek ????????? (kaustikós, “burning”).

Pronunciation

• enPR: kôs't?k, k?s't?k, IPA^(key): /?k??st?k/, /?k?st?k/
• Rhymes: -??st?k

Adjective

caustic (comparative more caustic, superlative most caustic)

1. Capable of burning, corroding or destroying organic tissue.
2. (of language, etc.) Sharp, bitter, cutting, biting, and sarcastic in a scathing way.
   • 1853, Charlotte Brontë, Villette

     Madame Beck esteemed me learned and blue; Miss Fanshawe, caustic, ironic, and cynical

   • c. 1930, W.H.Auden, "The Quest"

     though he came too late / To join the martyrs, there was still a place / Among the tempters for a caustic tongue / / To test the resolution of the young / With tales of the small failings of the great

Synonyms

• (capable of destroying tissue): acidic, biting, burning, corrosive, searing
• (severe, sharp): bitchy, biting, catty, mordacious, nasty, sarcastic, scathing, sharp, spiteful, vitriolic

Derived terms

Related terms

Translations

Noun

caustic (plural caustics)

1. Any substance or means which, applied to animal or other organic tissue, burns, corrodes, or destroys it by chemical action; an escharotic.
2. (optics, computer graphics) The envelope of reflected or refracted rays of light for a given surface or object.
3. (mathematics) The envelope of reflected or refracted rays for a given curve.
4. (informal, chemistry) Caustic soda.

Derived terms

• lunar caustic

Translations