The American Heritage® Dictionary of the English Language, 4th Edition
n. A factor that renders the administration of a drug or the carrying out of a medical procedure inadvisable: A previous allergic reaction to penicillin is a contraindication to the future use of that drug.
n. A factor or symptom which makes the prescribed treatment inadvisable.
the GNU version of the Collaborative International Dictionary of English
n. An indication or symptom which forbids the method of treatment usual in such cases.
The Century Dictionary and Cyclopedia
n. In medicine, an indication from some peculiar symptom or fact that forbids the method of cure which the main symptoms or nature of the disease would otherwise call for. Also counter-indication.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. (medicine) a reason that makes it inadvisable to prescribe a particular drug or employ a particular procedure or treatment
Word Usage
"F. CONTRAINDICATIONS: A contraindication is a specific situation in which a drug, procedure, or surgery should NOT be used, because it may be harmful to the patient."