the GNU version of the Collaborative International Dictionary of English
v. To grow or make tough, or tougher.
The Century Dictionary and Cyclopedia
Specifically, of copper, in its metallurgy, the elimination of the foreign metals as oxids and of copper oxid itself, changing the qualities of the cast from brittleness to ductility.
To grow tough or tougher.
To make tough or tougher.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
v. make tough or tougher
Word Usage
"You gotta fuckin toughen up with the cold and fuckin dealin with rugged not you average fuck around kinda guy."