1.
[syn: opportunist, opportunistic, timeserving]
The Collaborative International Dictionary of English v.0.48:
opportunistic \opportunistic\ adj.
1. taking immediate advantage, often unethically, of any
circumstance of possible benefit; practising opportunism.
[WordNet sense 1]
Syn: opportunist, timeserving.
[WordNet 1.5]
2. (Med.) Causing disease only when the immune system of the
host has been weakened, or other damage to the host
provides special opportunity for invasion; -- of
microorganisms or infectious diseases; as, opportunistic
pathogens may infect a burn site; AIDS predisposes a
patient to opportunistic infection.
[PJC]
WordNet (r) 3.0 (2006):
opportunistic
adj 1: taking immediate advantage, often unethically, of any
circumstance of possible benefit [syn: opportunist,
opportunistic, timeserving]