Meaning of “Yume migachi(夢見がち)”

“Yume migachi(夢見がち)” means “tend to think about like a dream frequently” or kind of “dreamy” or “romantic” or “head in the clouds”.
“Yume(夢)” means “dream”.
“Mi(見)” means “See”.
“[Verb] + Gatchi(がち)” means tend to [verb].

Example Conversation

A: What were you like when you were a kid?
B: Umm…maybe I was “Yume migachi(夢見がち)” girl.

A: 子どものときはどんな子だった？
B: うーん、夢見がちな少女だったかな