1. (

• 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 ;

2. (

• 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" ;