1) Absent-minded, to a Brit 2) Disorganised, unpredictable 3) Foolish 4) Lacking sense or discretion 5) Lost in thought 6) Rattlebrained 7) Rattlepated 8) Scatterbrained 9) Showing preoccupation 1) Absentminded 2) Foolish 3) Frivolous 4) Inattentive 5) Rattlebrained 6) Rattlepated 7) Scatterbrained 
Scatty is slang for slightly mad.