Synonyms for Opportunist (same or very similar meaning)
WordNet sense 1 (a person who places expediency above principle):
self-seeker
WordNet sense 2 (taking immediate advantage, often unethically, of any circumstance of possible benefit):
opportunistic, timeserving
WordNet sense 3 (serving to promote your interest):
expedient
From the ODE community, based on WordNet
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