A person who creates crossword puzzles, or someone who regularly solves them.
From 'crossword' (itself a 20th-century compound of 'cross' and 'word') combined with '-er' suffix indicating an agent noun. The term emerged in the 1920s as crosswords became a cultural phenomenon.
The first crossword puzzle appeared in a Sunday newspaper on December 21, 1913, and crossworders became so obsessed that newspapers began printing them daily by the 1920s—critics called them 'a menace to civilization,' yet they've outlasted almost every other puzzle fad by over a century.
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