rattlebrained, rattlepated, scatterbrained, scatty -- (lacking sense or discretion; "his rattlebrained crackpot ideas"; "how rattlepated I am! I've forgotten what I came for"- Glenway Westcott)
absent, absentminded, abstracted, scatty -- (lost in thought; showing preoccupation; "an absent stare"; "an absentminded professor"; "the scatty glancing quality of a hyperactive but unfocused intelligence")
(TTS Sound)
