1. rattlebrained, rattlepated, scatterbrained, scatty

lacking sense or discretion

Example Sentences:
'his rattlebrained crackpot ideas'
'how rattlepated I am! I've forgotten what I came for'

Synonyms

• rattlebrained
• rattlepated
• scatty

2. flighty, flyaway, head-in-the-clouds, scatterbrained

guided by whim and fancy

Example Sentences:
'flighty young girls'

Synonyms

• flighty
• flyaway
• head-in-the-clouds