To sneak is defined as to move around or do something in a quiet or cowardly way.(verb)
An example of to sneak is to creep up behind someone and scare her.
The definition of a sneak is a cowardly person or a trickster.(noun)
An example of a sneak is someone who does questionable things in a quiet way to avoid being noticed.
Sneak means done without warning in an unknown, secret or quiet manner.(adjective)
An example of sneak used as an adjective is "sneak attack" which means a surprise attack.
See sneak in Webster's New World College Dictionary
Origin: prob. < OE *snecan, akin to snican, to crawl: for IE base see snail
See sneak in American Heritage Dictionary 4
verb sneaked sneaked also snuck (snŭk), sneak·ing, sneaks verb, intransitive
Origin: Probably akin to Middle English sniken, to creep
Origin: , from Old English snīcan. Usage Note: Snuck is an Americanism first introduced in the 19th century as a nonstandard regional variant of sneaked. Widespread use of snuck has become more common with every generation. It is now used by educated speakers in all regions. Formal written English is more conservative than other varieties, of course, and here snuck still meets with much resistance. Many writers and editors have a lingering unease about the form, particularly if they recall its nonstandard origins. And 67 percent of the Usage Panel disapproved of snuck in our 1988 survey. Nevertheless, an examination of recent sources shows that snuck is sneaking up on sneaked. Snuck was almost 20 percent more common in newspaper articles published in 1995 than it was in 1985. Snuck also appears in the work of many respected columnists and authors: “He ran up huge hotel bills and then snuck out without paying” (George Stade). “He had snuck away from camp with a cabinmate” (Anne Tyler). “I ducked down behind the paperbacks and snuck out” (Garrison Keillor).
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