/ ˌɒpəˈtjuːnɪst; NAmE ˌɑːpərˈtuː-/ (also op·por·tun·is·tic ) adjective
[ usually before noun ] (often disapproving ) making use of an opportunity, especially to get an advantage for yourself; not done in a planned way :
an opportunist crime
► op·por·tun·ist noun :
80% of burglaries are committed by casual opportunists.
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WORD ORIGIN
late 19th cent.: from opportune + -ist .