Well, one way is just by distinguishing the terms “anarchistic socialism” and “state socialism.” Francis Tandy (a follower of Tucker) used the term “voluntary socialism.” Today, Kevin Carson likes to use the term “free market anti-capitalism”.

If more than two or three words are needed, you can explain that, even though most people today use “socialism” to refer only to state socialists, anarchistic socialism has been around as part of the socialist movement longer than Marxism and Social Democracy have, and that anarchistic socialism is based on the idea that workers should own the means of production, either individually or as part of voluntary associations, rather than the government owning the means of production, as state socialists suggest. You might also point interested parties to Benjamin Tucker’s essay, “State Socialism and Anarchism: How Far They Agree and Wherein They Differ,” which explicitly mentions Proudhon and his ideas, and is, I think, one of the finest discussions of the distinction ever put to paper.