Obstructionism is when someone tries to stop or slow a legal or political process, not by winning the argument, but by getting in the way — talking for hours, raising endless objections, missing meetings on purpose, blocking a vote. You hear it most about parliaments, courts, and committees. It is a formal, slightly accusing word: newspapers use it when they think a party is delaying on purpose. Though actually, the people doing it often say they are just asking careful questions or protecting the public. It is delay as a tactic, not simply voting no.