Entryism was an acquisition into political vocabulary in the 1970s, though it covered a far from new phenomenon. It referred then to the attempts by members of extreme political movements to join, and take control of, more moderate and established...

Entryism (or entrism or enterism) is a political tactic by which an organisation encourages members to infiltrate another organisation in an attempt to gain recruits, or take over entirely. In situations where the organisation being "entered" is hostile...