a portmanteau of the words "chow down" and "down syndrome," meaning the loss of mental acuity following a hefty meal; aka food coma.

When somebody is acting liking a debbie downer, but is being retarded about it

being completly obsessed with system of a down

The physical state following a good dicking in which you find yourself dazed, both mentally and physically.

When a person will say that they swear down to a multitude of statements, potentially even those that are not in fact true. They swear down so much that it even seems that they have a chronic obsession with swearing down, and their opinion becomes invalidated as such.

Tumblr Down Syndrome occurs when "edgy" teenage attention whores spend all their spare time on Tumblr.

Symptoms include:
1Feminazism
2Cutting ones own wrists in attempt to appear "edgy"
3Hating on cis white males
4Believing "cis" is an insult
5Writing shitty poetry

ie:

Roses are red,

Violets are blue,

I want to kill myself.

6Listening to "obscure" bands such as mcr an 5sos
7Hating on one for having an opinion
8Creating cringey/cancerous fandoms
9Spewing bullshit via keyboard
10Pretending to be LGBT to appear "cooler"

When you are really pissed off at someone who is normal(not retarded in anyway) and has a slightly down syndrome look face, you yell at them "what the fuck are you looking at, you down syndrome motherfucker!! This releases stress and puts a great big smile on your face. Try it today!