duckling

A person or thing once considered unattractive or unlikely to succeed that becomes beautiful or successful in time. The phrase refers to Hans Christian Andersen's fairy tale of an ugly duckling that grows up to be a beautiful swan. The phrase can apply to physical appearance or to the level of success of something. I thought that fledgling company would dissolve in months. No one foresaw that it was just an ugly duckling and would have great success. Mary went unnoticed in high school but she's gorgeous now—a real ugly duckling!

someone or something that is ugly and not successful when they are young or new, but which develops into something beautiful and successful The most successful company was last year's ugly duckling.

A homely or unpromising individual who grows into an attractive or talented person, as in She was the family ugly duckling but blossomed in her twenties. This term alludes to Hans Christian Andersen's fairy tale about a cygnet hatched with ducklings that is despised for its clumsiness until it grows up into a beautiful swan. The tale was first translated into English in 1846, and the term was used figuratively by 1871.