contraindication

antonym: indication
https://doi.org/10.1351/goldbook.15596
Any condition that renders some particular line of treatment improper or undesirable.
Source:
PAC, 2007, 79, 1153. (Glossary of terms used in toxicology, 2nd edition (IUPAC Recommendations 2007)) on page 1197 [Terms] [Paper]