The American Heritage® Dictionary of the English Language, 4th Edition
n. One, such as a person or corporation, that makes or gives a promise, assurance, or pledge typically relating to quality, durability, or performance.
the GNU version of the Collaborative International Dictionary of English
n. One who makes or gives a guaranty; a warrantor; a surety.
n. One who engages to secure another in any right or possession.
The Century Dictionary and Cyclopedia
n. One who makes a guaranty.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. one who provides a warrant or guarantee to another
Word Usage
"But the third possibility, which is the central concern of Madrick's book, has not yet been the subject of serious public debate: to use government as long-term guarantor of America's (and indirectly the world's) economic stability, as provider of widespread opportunity, and as partner with the private sector in restoring long-term stable growth."