build castles in the air
To have any desire, idea, or plan that is unlikely to be realized; to imagine visionary projects or schemes; to have an idle fancy or a pipe dream; to daydream.
Meaning adapted from Wiktionary, available under CC BY-SA 4.0.
“Stop building castles in the air and focus on your real work.”
“You are building castles in the air if you think this old car will fly.”
“She builds castles in the air during every long meeting at the office.”
“He spent all afternoon building castles in the air about winning the lottery instead of studying for his exams.”
“My brother keeps building castles in the air about starting a tech company, but he has not even learned how to write code yet.”
“Instead of building castles in the air about moving to a tropical island, we should save money for a small apartment in the city.”
“While she often built castles in the air regarding her future career, she lacked the practical discipline required to turn those grand visions into reality.”
first recorded 14th c.
The first term dates from the late 1500s. A variant, castles in Spain (or châteaux en Espagne), was recorded in the Roman de la Rose in the 13th century and translated into English around 1365.
- 01
air one's dirty laundry in public
To reveal one's sordid secrets to the public.
- 02
air one's dirty linen in public
Synonym of air one's dirty laundry in public.
- 03
air out
To expose to air; to leave open or spread out, as to allow odor or moisture to dissipate.
- 04
air rage
Aggressive, disruptive behaviour on an aircraft.
- 05
air sandwich
A strategy that has high-level direction and low-level operations, but little in the middle.
- 06
blow hot air
To engage in empty or exaggerated talk that lacks substance, credibility, or truth; to bluster.
- 07
breath of fresh air
Something relieving, refreshing, or new.
- 08
build a better mousetrap
To create a new product, method, or idea that is better than an existing version of something already common or widely used.
Last updated August 10, 2026