v. To give formal consent to; make officially valid.
the GNU version of the Collaborative International Dictionary of English
v. To approve and sanction; to make valid; to confirm; to establish; to settle; especially, to give sanction to, as something done by an agent or servant
The Century Dictionary and Cyclopedia
To confirm; establish; settle conclusively or authoritatively; make certain or lasting.
To validate by some formal act of approval; accept and sanction, as something done by an agent or a representative; confirm as a valid act or procedure.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
v. approve and express assent, responsibility, or obligation
Word Usage
"Refusing to ratify is no longer an option: the only way to unpick this will be by way either of complete renegotiation or of entering into a derogation of the Treaty."