To shutdown a machine, typically a computer. Opposite to reboost
I am going to have to deboost this computer because it has completely locked up!
by Clifford H. Boost November 27, 2006
When your bald ass fucking friend won't go mountain biking with you.
Ahhh, common Yani, you're such a deboost for not biking today!
by yani is katchal April 21, 2011