v. to bring or reduce to the state or condition of a beast
the GNU version of the Collaborative International Dictionary of English
v. To make bestial, or like a beast; to degrade; to brutalize.
The Century Dictionary and Cyclopedia
To make like a beast; bring or reduce to the state or condition of a beast.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
v. make brutal and depraved; give animal-like qualities to
Word Usage
"He was even caricatured and abused for his attempt to "bestialize" his species by the introduction into their systems of diseased matter from the cow's udder."