in short, it reads across as ‘one-hundred percent’, meaing ‘the most’.

1)full effort; all; maximal exertion (as applying to a sport, usually)

2)completion (commonly of a particular RPG):
a] in utterly the sumpremest, truest sense of the word;
or
b.] virtually, or for intensive or practical purposes (can vary)

Note that that the second use of ‘100%’ can serve as many parts of speach simply by adding a different suffix.
{100% = completion to the fullest extent}
100%ly = adverb
100%'r or 100%er = person (noun)
100%'d or 100%ed = past-tense form of verb (usually transitive)
. . . and so on . . .
1) The football coach told us not to give our 100%, but to give him our 110-or-112%.

2) Mike thought th't he 100%'d his video-game savefile, until he later found out, became aware, of everything he missed, at none other than the GFs messageboard, at which point he displayed himself as a genuine n00b.
by Victor Van Styn October 13, 2005

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It is the very best it could be.
That girl is 100%
by Huw Cake March 03, 2004

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Lotsa space for your liquids.

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Lotsa space for your liquids.

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Your favorite word on a white mug.

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One side has the word, one side has the definition. Microwave and dishwasher safe. Lotsa space for your liquids.

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The Urban Dictionary T-Shirt

Soft and offensive. Just like you.

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The Urban Dictionary T-Shirt

Smooth, soft, slim fit American Apparel shirt. Custom printed. 100% fine jersey cotton, except for heather grey (90% cotton).

Buy the t-shirt