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The most comfortable thing one can wear, there is no denying it.
Sally experienced a cozy wonderland as she put on her fuzzy onesie.
by Cosmello January 11, 2015
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Onesie comes from the word "one" and means a one-piece suit, usually in the form you use for lazy days at home. It is also used for one-piece snowsuits and one-piece motorcycle suits. The word is sometimes spelled onesy.

The name may be derived from the registered trademark Onesies®, which is a range of clothes for infant children. The word onesie (in singular) does however, in modern usage, more often mean a suit in adult size.
When I come home from work, I just like to change into my onesie and watch TV.
by EliasG June 04, 2013
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The outfit necessary to make any event just that much better.
It’s time to party! Does everyone have their onesies?!
via giphy
by Sneaky Unicorn February 15, 2018
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a single cigarette sold over the counter by a retail establishment, instead of a pack of 20. useful in New York if you don't have the $8 for a pack. also useful for the quitting smoker who just needs one nicotine hit to take the edge off. onesie's are illegal in some states - eg Illinois 2009
"he sold me a onesie with a cup of coffee"
by mak108 August 22, 2009
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