
Moon about
Daydreaming Focus
Use 'moon about' when you mean someone is distracted by their thoughts and not focused on their surroundings. 
Lighthearted Tone
'Moon about' often has a lighthearted, slightly whimsical tone; it's not usually used for serious situations. 
Romantic Connotation
'Moon about' can imply that someone's aimless behavior is due to romantic thoughts or feelings. 