opportunistic

adjective

1. adhering to a policy of opportunism; practicing opportunism.
2. Pathology.
   1. (of a microorganism) causing disease only under certain conditions, as when a person’s immune system is impaired.
   2. (of a disease or infection) caused by such an organism: Pneumocystis pneumonia is an opportunistic disease that often strikes victims of AIDS.

adjective

1. of or characterized by opportunism
2. 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

adj.1889, see opportunist + -ic. Related: Opportunistically. adj.

1. Of or relating to an organism capable of causing disease only in a host whose resistance is lowered.
2. Of or relating to a disease caused by an opportunistic organism.