Top Definition
Emphatically exhibits the sincerity of your seriousness. The classic use is to close a letter with it.
Dear Urban Dictionary:


Thank you in advance for considering “sinseriously” in your Urban Dictionary.

Were sinseriously to be included in The Urban Dictionary, that would make my day, perhaps even my week.

Sinseriously,
Cyprus Denton Fekks
by Cyprus Denton Fekks February 19, 2010

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To be sincere and serious at the same time.
"Dude, sinseriously, im sorry"
by LilRayRay July 24, 2008

The Urban Dictionary Mug

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Lotsa space for your liquids.

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The Urban Dictionary Mug

Your favorite word on a white mug.

Create a mug

The Urban Dictionary Mug

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).

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"sinseriously" is a super fun loving word that can be used to sign a card with. It is a great way to let someone know how much you care about them and that you are serious and sincere about everything you wrote on a letter. It is a cherry on top.
Thanks for being my friend and i hope you enjoy your present

"Sinseriously", Joe
by valkayerie July 09, 2011

The Urban Dictionary Mug

Lotsa space for your liquids.

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The Urban Dictionary Mug

Lotsa space for your liquids.

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The Urban Dictionary Mug

Your favorite word on a white mug.

Create a mug

The Urban Dictionary Mug

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

Buy the mug

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
Being seriously sincere. Sincere & serious about it.
girl: are you serious? guy: Sinseriously !
by Berjmaster November 27, 2015

The Urban Dictionary Mug

Lotsa space for your liquids.

Buy the mug

The Urban Dictionary Mug

Lotsa space for your liquids.

Buy the mug

The Urban Dictionary Mug

Your favorite word on a white mug.

Create a mug

The Urban Dictionary Mug

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

Buy the mug

The Urban Dictionary T-Shirt

Soft and offensive. Just like you.

Buy the t-shirt

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