to·bog·gan 
(tə-bŏgən)
(tə-bŏgən)n.
A long, narrow, runnerless sled constructed of thin boards curled upward at the front end.
intr.v. to·bog·ganed, to·bog·gan·ing, to·bog·gans
1. To coast, ride, or travel on a toboggan.
2. Slang To decline or fall rapidly: His good fortune has tobogganed.
[Canadian French tobagan, from Mi'kmaq topaghan.]
to·boggan·er, to·boggan·ist n.
toboggan