A person, especially a small or unimportant one, who fusses excessively or worries about trivial matters.
From 'fuss' plus 'pot' (possibly used as a derogatory suffix, as in 'hotspot'), becoming a colorful British term for a fussy person, popularized in the 20th century.
British English is wonderfully creative with combining common words into insults—'fusspot' sounds annoyed and affectionate simultaneously, which is very British indeed.
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