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
1 more definition
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