adhering to a policy of opportunism; practicing opportunism.
Pathology. (of a microorganism) causing disease only under certain conditions, as when a person's immune system is impaired. (of a disease or infection) caused by such an organism: Pneumocystis pneumonia is an opportunistic disease that often strikes victims of AIDS.
of or characterized by opportunism
(med) (of an infection) caused by any microorganism that is harmless to a healthy person but debilitates a person whose immune system has been weakened by disease or drug treatment