A syndicalist is someone who advocates for the emancipation of the working class only through economic means, and abstains from political struggle. Syndicalists are usually active in trade or labor unions. They typically denounce the role of a organized political working class party as authoritarian. Syndicalist theory in many ways can be seen as similar to anarchism, and different terms of classification such as "anarcho-syndicalism" or "anarcho-communism" can be used to describe this particular ideology.
The IWW has a strong syndicalist tradition in that they dont advocate political struggle, and see the trade union as the only essential route towards working class emancipation.