/ Dictionary / Index R rattlebrained: Meaning and Definition of Find definitions for: rat•tle•brained Pronunciation: (rat'l-brānd"), [key] — adj. foolish; flighty; scatterbrained. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: rattlebrained (Thesaurus) rattlebrain rattle-bush Related Content Daily Word Quiz: placid Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language