the GNU version of the Collaborative International Dictionary of English
adj. Causing constriction of the blood vessels; These nerves are also called vasohypertonic.
n. A substance which causes constriction of the blood vessels. Such substances are used in medicine to raise abnormally low blood pressure.
The Century Dictionary and Cyclopedia
Serving to constrict vessels when stimulated, as certain nerves: opposed to vasodilator. Both are included under vasomotor.
n. That which causes contraction of the blood-vessels: applied to nerves and to certain drugs.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. any agent that causes a narrowing of an opening of a blood vessel: cold or stress or nicotine or epinephrine or norepinephrine or angiotensin or vasopressin or certain drugs; maintains or increases blood pressure
Word Usage
"Its all about caffeine being a vasoconstrictor and everything starting to open up when the caffeine gets low."