In Roblox, a obstacle course.
In Minecraft, obby is short for obsidian, commonly used on faction servers.
Roblox:

Player1: Hey kid, do you want to play a obby?

Noob: N0 thx m8 i b4d at 0🅱🅱ys xD lit saveage famm

Minecraft:

Player1: Anybody selling some obby? I need to build a new base.

Player2: I'll sell ya a stack of obby for 50,000.
by LitBot February 18, 2018
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Short for obstacle course. Often used on the website "ROBLOX".
lets got to that obby
by anotherusername1111 February 13, 2010
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You: Hey wanna go to the easiest obby?
Noob: What's an obby?
by Octus The Robot May 01, 2011
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Obby= o bby= oh baby.
Pronounced: aw bee.

See:oh baby,babeh.
Guy: *smacks ass*
Girl: obby!
by Jay :3 June 23, 2008
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Nothing specific, just a word I thought of in the shower. This is a great word to set as a username or to spam with. Brilliant to annoy people.
Person 1:

obby
obby
obby
obby

obby

Person 2:

Your block button looks real juicy right now.
by obby December 06, 2020
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the name given to the one kid in every group of friends that you keep around only to make fun of.

no matter what you do, where you go, obby will find you and stand at your side whether you like it or not.
"hey obby, come on over you cunt bag"
"man, why is that cunt bag obby here?"
by Faux Vie August 10, 2007
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