A reasoned idea, plan, or argument is one that comes from careful thought, so it feels sensible. If someone gives a reasoned answer, they have looked at the facts and thought them through; they did not just speak from a sudden feeling. You meet this word a lot in essays, news, and serious talk: a reasoned debate, a reasoned decision. It is a little formal. Though actually, students often mix reasoned with reasonable, and they are not the same. Reasonable often means “fair” or “not too much,” as in a reasonable price. Reasoned is narrower: it tells you how the thinking was done — slowly, with reasons. A reasoned argument can still be wrong; it just was not thrown together. The same spelling is also the past of the verb reason (“She reasoned that it was safer to wait”), but the meaning here is the adjective: built on careful thought.