showing poor taste or cheap quality, or slightly sticky or adhesive to the touch.
From 'tack,' meaning a small nail (1600s), from English dialect. The sticky meaning came first—a tacky substance is like a wet nail. The 'bad taste' meaning emerged in American English (1800s), possibly from cheap, sticky varnish.
The word 'tacky' connects two completely different meanings through one strange bridge—it started meaning 'sticky' (like wet glue or varnish), and Americans expanded it to mean 'cheaply made and sticky-looking,' which eventually meant 'just bad taste' in general!
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