exploiting chances offered by immediate circumstances without reference to a general plan or moral principle 机会主义的 the change was cynical and opportunistic. 该改变是愤世嫉俗和机会主义的。 ■(Ecology)(of a plant or animal) able to spread quickly in a previously unexploited habitat (生态)(动植物)能在新的栖息地迅速分布的 ■(Medicine)(of a micro-organism or an infection caused by it) rarely affecting patients except in unusual circumstances, typically when the immune system is depressed (医)(微生物)机会感染的