Dissuasion is the act of talking someone out of a plan. You use words — reasons, a warning, a quiet please-don't — so the person chooses not to do the thing. Nobody is banning them; you are not using a rule or a punishment. You are trying to turn their mind. The everyday verb is dissuade; dissuasion is the noun, and it sounds a little careful and formal. A parent, a teacher, or a newspaper might speak of dissuasion. A friend would more often say I talked her out of it. It sits next to persuasion, though actually it pulls the other way: persuasion tries to move someone toward a thing, dissuasion tries to move them away. Soft dissuasion can be a look. Strong dissuasion can be a long, worried talk. The feeling is often care, not attack.