sourest

adjective

1. 1

   Having an acidic, sharp or tangy taste.

   “Lemons have a sour taste.”

2. 2

   Made rancid by fermentation, etc.

   “Don't drink that milk; it's turned sour.”

3. 3

   Tasting or smelling rancid.

   “His sour breath makes it unpleasing to talk to him.”

4. 4

   (of a person's character) Peevish or bad-tempered.

   “He gave me a sour look.”

5. 5

   (of soil) Excessively acidic and thus infertile.

   “a sour marsh”

6. 6

   (of petroleum) Containing excess sulfur.

   “sour gas smells like rotten eggs”

7. 7

   Unfortunate or unfavorable.

8. 8

   Off-pitch, out of tune.