Something spectacular, crazy or "insane" having to do with skateboards, especially a longboard that features large soft wheels made of soft urethane often called "thane." Hence, inthane is created as word play when combining insane and thane.
Did you see that gnarly 50 foot stand up slide he did... that was inthane!

We bombed hills that were totally inthane!
by Bergen County Bombers April 25, 2011
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