--------Literally, not following (logically), illogical, not connected to anything previously said or (as a noun) a statement not following logically from what was previously said. It originates in logic, where it refers to an inference not following from the premise.
--------This is a pretty harsh criticism of someone's logical powers, so it should be applied directly only in extreme circumstances and indirectly only with cause. "What she is saying sounds fine but if you think for a minute, you see that it is non sequitur." (não tem lógica / não é lógico / não faz sentido) Or, as a noun: "If his non sequiturs (foras?) weren't so funny, he would be a detriment to the negotiations."