Open English Wordnet
Adjectives
(s)rattlebrained, rattlepated, scatterbrained, scattylacking sense or discretion“his rattlebrained crackpot ideas”, “how rattlepated I am! I've forgotten what I came for” (Glenway Westcott)
(s)absent, absentminded, abstracted, scattylost in thought; showing preoccupation“an absent stare”, “an absentminded professor”, “the scatty glancing quality of a hyperactive but unfocused intelligence”