Learn how to say Opportunistic correctly in English with this tutorial pronunciation video.
Oxford dictionary definition of the word opportunistic:
exploiting immediate opportunities, especially regardless of planning or principle:
an opportunistic political lightweight
Ecology (of a plant or animal) able to spread quickly in a previously unexploited habitat:
opportunistic populations colonizing new substrates
Medicine (of a microorganism or an infection caused by it) affecting patients only or chiefly when the immune system is depressed.