Real Dictionary

opportunism
uncountable noun: If you refer to someone's behaviour as opportunism, you are criticizing them for taking advantage of any opportunity that occurs in order to gain money or power, without thinking about whether their actions are right or wrong.

opportunism in American English
the practice or policy of adapting one's actions, judgments, etc. to circumstances, as in politics, in order to further one's immediate interests, without regard for basic principles or eventual consequences
noun: the policy or practice, as in politics, business, or one's personal affairs, of adapting actions, decisions, etc., to expediency or effectiveness regardless of the sacrifice of ethical principles