definition of
scatterbrained

[1] #1 scatterbrained s. [rattlebrained, rattlepated, scatty] lacking sense or discretion; "his rattlebrained crackpot ideas"; "how rattlepated I am! I've forgotten what I came for"- Glenway Westcott. wn

[2] #2 scatterbrained s. [flighty, flyaway, head-in-the-clouds] guided by whim and fancy; "flighty young girls". wn