Definition.com
The Law of fashion (n.) governs most men more than God or the magistrate: they hope to be forgiven by God and to escape the law, but no one escapes his club's contempt.
2 definitions
Definition.com
The Law of fashion (n.) or of opinion is the power citizens retain after resigning the disposing of all their force to the public, the power of thinking well or ill of those they live amongst, and by that approbation and dislike they establish what they will call virtue and vice.