the GNU version of the Collaborative International Dictionary of English
adj. Loosed from the bridle, or as from the bridle; hence, unrestrained; licentious; violent.
The Century Dictionary and Cyclopedia
Not having a bridle on; hence, unrestrained; unruly; violent; licentious.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
adj. not restrained or controlled
Word Usage
"On nuclear weapons, the Iranian president deplores what he calls unbridled expansion and testing of more powerful warheads, apparently implicating the United States."