Acting in a secretive, underhanded, or deceptive manner; characterized by stealth and attempts to avoid detection.
From 'sneak' (origin uncertain, possibly from Old English snican 'to creep') + -y suffix. 'Sneak' appeared in the 16th century, initially meaning to crawl or creep, later developing the sense of moving stealthily with dishonest intent.
The word 'sneak' has an oddly uncertain etymology - linguists aren't sure where it came from, making it somewhat sneaky itself! Some connect it to Old English 'snican' meaning to creep, while others suggest it might be related to the sound of stealthy movement.
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