This idiom describes relaxing, behaving freely, or letting go of inhibitions, as if loosening one’s hair from a formal style to unwind. It conveys carefree enjoyment, often used in social or personal contexts to depict shedding restraint. The phrase carries a tone of fun, liberation, or encouragement, reflecting cultural values of balance and the human tendency to seek release. Its imagery of loose hair evokes a casual shift, resonating in scenarios like parties or downtime. The idiom celebrates spontaneity, making it a lively metaphor for unwinding.

The phrase likely originated in 19th-century Britain, tied to women loosening tightly pinned hair after formal events, as noted in etiquette guides. Its earliest recorded use appears in *The Times* (1850s), for social relaxation. The idiom gained traction in the early 20th century, amplified by flapper culture and media, notably in *The Great Gatsby* (1925) by F. Scott Fitzgerald. Its spread was boosted by pop culture, enduring for its vivid imagery and applicability to leisure, especially in the U.K. and U.S.