sour

The definition of sour is something with an acidic taste, or someone who is resentful or angry.

(adjective)

Milk that has gone bad is an example of something that would be described as sour.
The unsweetened juice of a lemon is an example of something that would be described as sour.
A person with a grumpy and rude personality who is angry all the time is an example of someone who would be described as having a sour personality.

Sour is to cause dissatisfaction, or is to go bad or rotten.

(verb)

When you really like a band but then they come out against something you believe in and you really don't respect them after that, this is an example of when you sour on the band.
When milk goes bad, this is an example of when it sours.

See sour in Webster's New World College Dictionary

adjective

having the sharp, acid taste of lemon juice, vinegar, green fruit, etc.
made acid or rank by or as by fermentation: sour milk
1. cross, bad-tempered, peevish, morose, etc.: a sour mood
2. ill-disposed and bitter: sour toward former associates
below what is usual or normal; poor; bad: his game has gone sour
distasteful or unpleasant
gratingly wrong or off pitch: a sour note
excessively acid: said of soil
tainted with sulfur compounds: said of gasoline, etc.

Origin: ME soure < OE sur, akin to Ger sauer, ON sūrr < IE *suro-, sour, salty > Latvian sũrs, salty, bitter

noun

that which is sour; something sour
☆ a cocktail made with lemon or lime juice, sugar, and, usually, soda water: a whiskey sour

transitive verb, intransitive verb

to make or become sour: the milk will sour, soured on life

Related Forms:

See sour in American Heritage Dictionary 4

adjective sour·er, sour·est

Having a taste characteristic of that produced by acids; sharp, tart, or tangy.
Made acid or rancid by fermentation.
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.
b. Not having the correct or properly produced pitch: a sour note.
Of or relating to excessively acid soil that is damaging to crops.
Containing excessive sulfur compounds. Used of gasoline.

noun

The sensation of sour taste, one of the four primary tastes.
Something sour.
A mixed drink made especially with whiskey, lemon or lime juice, sugar, and sometimes soda water.

tr. & intr.v. soured, sour·ing, sours