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Synonyms

insoluble

American  
[in-sol-yuh-buhl] / ɪnˈsɒl yə bəl /

adjective

  1. incapable of being dissolved.

    insoluble salts.

  2. incapable of being solved or explained.

    an insoluble problem.


insoluble British  
/ ɪnˈsɒljʊbəl /

adjective

  1. incapable of being dissolved; incapable of forming a solution, esp in water

  2. incapable of being solved

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

insoluble Scientific  
/ ĭn-sŏlyə-bəl /
  1. Not capable of being fully dissolved. Fats and oils are insoluble in water.


Other Word Forms

  • insolubility noun
  • insolubleness noun
  • insolubly adverb
  • semi-insoluble adjective

Etymology

Origin of insoluble

1350–1400; < Latin insolūbilis; replacing Middle English insolible < Middle French insoluble < L. See in- 3, soluble

Explanation

Let a bottle of salad dressing stand on the table for a few hours and you will notice that it has separated into layers. That's because oil is insoluble or is not capable of being dissolved. Insoluble comes from the Latin insolubilis meaning "that cannot be loosened." When a substance is insoluble, it cannot be dissolved or loosened in water. Similarly, a situation that is insoluble has no hope of being solved. When a marriage is beyond repair and cannot be fixed, it is insoluble.

Keep Reading on Vocabulary.com

Vocabulary lists containing insoluble

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

After the ghostly reflection of Frank Silva, a prop man, was inadvertently caught on camera, Lynch was inspired and cast Silva as the embodiment of insoluble evil.

From The Wall Street Journal • Apr. 17, 2026

"You could run into the extremes of eating too much, where if you're not drinking enough water to hydrate and exceed the amount of soluble and insoluble fiber, you can get constipated," Lee said.

From Science Daily • Mar. 8, 2026

Purple, savoy and green cabbage are also high in insoluble fiber, which Beitchman says is “the broom of the digestive system,” allowing waste to pass through more easily.

From Salon • Feb. 21, 2026

In the mouse model, oral arginine lowered amyloid plaque formation and reduced insoluble Aβ42 levels in the brain.

From Science Daily • Nov. 21, 2025

More than the question of compensation, then, the relocation problem was perilously close to insoluble.

From "Founding Brothers: The Revolutionary Generation" by Joseph J. Ellis