Acid — Meaning, Definition & Synonyms

noun adjective /ˈa-səd/

Meaning & Definition of Acid

Acid (noun)

  1. a sour substance; specifically, any of various typically water-soluble and sour compounds that in solution are capable of reacting with a base to form a salt, redden litmus, and have a pH less than 7, that are hydrogen-containing molecules or ions able to give up a proton to a base, or that are substances able to accept an unshared pair of electrons from a base
  2. something incisive, biting, or sarcastic
  3. lsd

Acid (adjective)

  1. sour, sharp, or biting to the taste
  2. sharp, biting, or sour in manner, disposition, or nature
  3. sharply clear, discerning, or pointed

Acid (adjective) — Senses, Synonyms & Antonyms

  1. causing or characterized by the one of the four basic taste sensations that is produced chiefly by acids

    "an acid-tasting medicine"

    similar: acidic, acidulous, sour, sourish, tart, tartish, vinegary
    related: dry, soured, unsweetened, pungent, sharp, tangy, zestful, zesty, zingy, astringent, puckery, hyperacid
    near: sweet, bland, smooth, flat, flavorless, insipid, savorless, tasteless, zestless, dilute, thin, watery, weak

  2. having or showing a habitually bad temper

    "with her acid personality, my aunt could be relied upon to bring some much-needed balance to the holiday gush"

    similar: bearish, bilious, bloody-minded (chiefly British), cantankerous, disagreeable, dyspeptic, ill-humored, ill-natured, ill-tempered, ornery, splenetic, surly
    related: choleric, crabby, cranky, crotchety, fussy, grouchy, grumpy, querulous, irascible, irritable, peevish, peppery, petulant, quick-tempered, short-tempered, snappish, snippy, testy, touchy, argumentative, contentious, contrary, cussed, angry, exasperated, indignant, irate, mad, upset, uptight, depressed, dour, glum, morose, sullen, anal, old-maidish, schoolmarmish
    opposite: amiable, good-humored, good-natured, good-tempered
    near: agreeable, amicable, congenial, friendly, pleasant, benign, gentle, kind, nice, sweet, bubbly, cheerful, cheery, effervescent, exuberant, high-spirited, joyful, lighthearted, lively, vivacious, content, glad, happy, calm, placid, serene, long-suffering, patient, tolerant

  3. marked by the use of wit that is intended to cause hurt feelings

    "a cultural gadfly known for an acid tongue that spares no one"

    similar: acerb, acerbic, acidic, acidulous, acrid, barbed, biting, caustic, corrosive, cutting, mordant, pungent, sarcastic, sardonic, satiric, scalding, scathing, sharp, smart-aleck, smart-alecky, smart-mouthed, snarky, tart
    related: brisk, cross, sharp-tongued, sour, sourish, spiky, tartish, incisive, keen, poignant, trenchant, cynical, dry, ironic, wry, facetious, flippant, tongue-in-cheek, acrimonious, bitter, resentful, vitriolic, harsh, rough, severe, stringent, abrupt, blunt, brusque, concise, crisp, curt, gruff, pithy, snippety, snippy, succinct, terse, backhanded, insincere
    near: amusing, droll, merry, playful, sportive, waggish, gentle, mild, bland, good-humored, good-natured, diplomatic, polite, smooth, suave, urbane, affable, cordial, genial, gracious, hospitable, sociable

Related Entry: Acid test (noun)

Acid test is a different word from Acid. The synonyms below are for acid test, not for acid.

  1. as in litmus test, litmus

    similar: litmus, litmus test, cross, crucible, fire, gauntlet, ordeal, trial, baptism, initiation, challenge, complication, difficulty, grief, grievance, hardship, rigor

Related Entry: Acid tests (noun)

Acid tests is a different word from Acid. The synonyms below are for acid tests, not for acid.

  1. as in litmus tests, litmuses

    similar: litmuses, litmus tests, crosses, crucibles, fires, gauntlets, ordeals, trials, baptisms, initiations, challenges, complications, difficulties, griefs, grievances, hardships, rigors

Synonyms, Thesaurus & Another Word for Acid

The most common words with a similar meaning to Acid:

Chiefly British: bloody-minded
acidic, acidulous, sour, sourish, tart, tartish, vinegary, bearish, bilious, cantankerous, disagreeable, dyspeptic, ill-humored, ill-natured, ill-tempered, ornery, splenetic, surly, acerb, acerbic, acrid, barbed, biting, caustic, corrosive, cutting, mordant, pungent, sarcastic, sardonic, satiric, scalding, scathing, sharp, smart-aleck, smart-alecky, smart-mouthed, snarky

Antonyms & Opposite Words for Acid

Words with the opposite meaning of Acid:

amiable, good-humored, good-natured, good-tempered

Related Words for Acid

dry, soured, unsweetened, tangy, zestful, zesty, zingy, astringent, puckery, hyperacid, choleric, crabby, cranky, crotchety, fussy, grouchy, grumpy, querulous, irascible, irritable, peevish, peppery, petulant, quick-tempered, short-tempered, snappish, snippy, testy, touchy, argumentative

Near Antonyms of Acid

sweet, bland, smooth, flat, flavorless, insipid, savorless, tasteless, zestless, dilute, thin, watery, weak, agreeable, amicable, congenial, friendly, pleasant, benign, gentle, kind, nice, bubbly, cheerful, cheery, effervescent, exuberant, high-spirited, joyful, lighthearted

Word Forms of Acid

Derived words: acidy (adjective), acidly (adverb), acidness (noun)

Origin & Etymology of Acid

borrowed from Medieval Latin acidum, going back to Latin, neuter of acidus acid:2

First known use: 1650

Vocabulary Lists & Topics for Acid

Words & Phrases Containing Acid

acid-fast, acid phosphatase, acid precipitation, acid rain, acid reflux, acid rock, acid snow, acid test

Frequently Asked Questions about Acid

What does "Acid" mean?

"Acid" means a sour substance; specifically, any of various typically water-soluble and sour compounds that in solution are capable of reacting with a base to form a salt, redden litmus, and have a pH less than 7, that are hydrogen-containing molecules or ions able to give up a proton to a base, or that are substances able to accept an unshared pair of electrons from a base. As an a noun and an adjective, it is defined as: a sour substance; specifically, any of various typically water-soluble and sour compounds that in solution are capable of reacting with a base to form a salt, redden litmus, and have a pH less than 7, that are hydrogen-containing molecules or ions able to give up a proton to a base, or that are substances able to accept an unshared pair of electrons from a base. It has 3 distinct senses.

What is another word for "Acid"?

Other words for "Acid" include acidic, acidulous, sour, sourish, tart, tartish, vinegary and bearish. The best synonym depends on which meaning of "Acid" you intend.

What are different ways to say "Acid"?

There are 122 words and phrases with a similar meaning to "Acid". Common alternatives include acidic, acidulous, sour, sourish, tart, tartish, vinegary, bearish, bilious and bloody-minded.

What is the opposite of "Acid"?

Antonyms of "Acid" include amiable, good-humored, good-natured and good-tempered. Near antonyms include sweet, bland, smooth and flat.

How do you use "Acid" in a sentence?

Examples of "Acid" in a sentence: "an acid-tasting medicine"; "with her acid personality, my aunt could be relied upon to bring some much-needed balance to the holiday gush"; "a cultural gadfly known for an acid tongue that spares no one".

Is "Acid" a noun, verb, or adjective?

"Acid" can be used as a noun and an adjective, depending on the context.

Is "Acid" useful for IELTS, TOEFL, and other English exams?

As a B2-level word, "Acid" is typical of Cambridge B2 First (FCE), IELTS band 5.5–6.5, TOEFL iBT 72–94, PTE Academic 59–75, TOEIC Listening & Reading 785+.

How do you pronounce "Acid"?

"Acid" is pronounced /ˈa-səd/.