Don't interrupt someone working intently on a puzzle. Chances are, you'll hear some crosswords.
Why this joke works
Cross Words at a Crossword
“Crosswords” names the grid puzzle built from intersecting answers. Separated into “cross words,” the phrase means irritated or angry remarks. Interrupting someone who is concentrating on a difficult puzzle could reasonably produce those remarks, so the setup supports both readings. The punchline does not alter pronunciation or invent a spelling; it simply restores a word boundary that the familiar compound noun normally hides.
A closer look
Advice That Becomes a Warning
The opening sounds like considerate advice about respecting someone’s concentration. “Chances are” then predicts a consequence, so listeners expect annoyance or a request for quiet. The final noun delivers exactly that outcome while naming the activity. The joke’s mildly formal wording makes the warning sound more authoritative than the small social offense deserves.
Fact behind the joke
The Crossword Began as a Word-Cross
The earliest crossword is commonly credited to Arthur Wynne and appeared in the New York World on December 21, 1913. It was presented as a “word-cross” puzzle; the format spread rapidly through American newspapers and the name became “crossword.” The joke playfully reverses that naming journey by separating the compound again.