Wiktionary
cap over the windmill
adv. (context idiomatic English) in a crazed manner
Usage examples of "cap over the windmill".
If you imagine that Tiffany would fling her cap over the windmill for a mere commoner you can't know her!
It might lead her to throw her cap over the windmill, but it found no answering chord in Miles.
The university was kindly hoping she'd thrown her cap over the windmill with one of father's research students, a bright lad called Elliot.
The Vicar, himself the son of a landed gentleman, had married the beautiful Miss Theale, who might have been expected to have done better for herself than to have thrown her cap over the windmill for a mere younger son, however handsome he might be.