adj. sour·er, sour·est
1. Having a taste characteristic of that produced by acids; sharp, tart, or tangy.
2. Made acid or rancid by fermentation.
3. Having the characteristics of fermentation or rancidity; tasting or smelling of decay.
a. Bad-tempered and morose; peevish: a sour temper.
b. Displeased with something one formerly admired or liked; disenchanted: sour on ballet.
a. Not measuring up to the expected or usual ability or quality; bad: a sour performance of the play.
b. Not having the correct or properly produced pitch: a sour note.
6. Of or relating to excessively acid soil that is damaging to crops.
a. Containing excessive levels of sulfur compounds, carbon dioxide, or both. Used of oil and natural gas.
b. Containing excessive levels of peroxides. Used of gasoline.
1. The sensation of sour taste, one of the four primary tastes.
2. Something sour.
3. A mixed drink made especially with whiskey, lemon or lime juice, sugar, and sometimes soda water.
tr. & intr.v. soured, sour·ing, sours
1. To make or become sour.
2. To make or become disagreeable, disillusioned, or disenchanted.
[Middle English, from Old English sūr.]
Synonyms: sour, acerbic, acid, acidic, tart1
These adjectives mean having a taste like that produced by an acid: sour lemons; an acerbic vinegar; the acid taste of guavas; a lightly acidic coffee; tart cherries.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2019 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.