brainful adjective 1noun 1forms 3 adjective1 •Characterized by brain activity; cerebral.We are “brainful” until we realize it. Then we can become mindful, at least momentarily, because our frame of reference is now larger. — 2015 noun1 •As much as one person can think about or hold in mind at one time.I can only usefully hold one brainful of detail at a time, and a thousand-line method contains way more than one brainful. — 2007 formsbrainfuls · more brainful · most brainful