White-shoe Definition

wītsho͝o, hwīt-

adjective

Of or being a long-established business known for reputable service and a wealthy clientele.

American Heritage

Designating or characteristic of a business company, esp. a law firm or brokerage, in which the partners belong almost exclusively to the white, Protestant, upper-class elite and are thought of as being conservative.

Webster's New World

(US, slang) Effeminate or immature.

Wiktionary

(US, slang) Establishment; pertaining to mainstream US social power-structures.

Wiktionary

noun

(US, slang) A stereotypical Ivy League student.

Wiktionary

Origin of White-shoe

From the white buckskin shoes once commonly worn by Ivy League undergraduates and considered typical dress of the American upper class

From American Heritage Dictionary of the English Language, 5th Edition
From white + shoe; their traditional footwear.

From Wiktionary