Internet Slang - adjective - an object which is old or obsolete but which is still cool; an object which is obsolete but is in actuality much cooler than the object which has replaced it.
"My friend's old thunderbird is obso1337."
by Knight9910 January 04, 2005
The legendary hacker who made kids rage in the game All Points Bulletin.
Gamer: Fuck you OBSO1337!
by nonyafckingbusiness June 18, 2011