Definition & Meaning of "sourhead"in English

What is the origin of the term "sourhead" and how is it used?

"Sourhead" is a slang term for a person regarded as bitter, unpleasant, or constantly negative. It likely appeared in English in the 19th or early 20th century, combining "sour" (evoking bitterness or displeasure) with "head" as a metaphor for the person's character or temperament. The term labels someone whose attitude or disposition is consistently disagreeable. It is mildly derogatory, used in informal or social contexts to criticize personality, and is generally light‑hearted rather than deeply offensive.