opportunistic

1. ADJ If you describe someone's behaviour as opportunistic, you are critical of them because they take advantage of situations in order to gain money or power, without thinking about whether their actions are right or wrong. 機(jī)會(huì)主義的[表不滿]

Many of the party's members joined only for opportunistic reasons. 這個(gè)政黨的許多成員入黨純粹是出於投機(jī)。