- 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
Antonym: wise (indirect, via foolish)
- flighty, head-in-the-clouds, scatterbrained - absent-mindedly irresponsible; "he said I was too flighty to be a good supervisor"
Antonym: responsible (indirect, via irresponsible)