a very plain child or unpromising thing that in time becomes or could become beautiful, admirable, important, etc.
Origin of ugly ducklingfrom a story by Hans Christian Andersen about a supposed ugly duckling that turns out to be a swan
One that is considered ugly or unpromising at first but has the potential to become beautiful or admirable in maturity.
Origin of ugly ducklingAfter The Ugly Duckling, a story by Hans Christian Andersen.
(plural ugly ducklings)
From a fairy tale of a duckling, considered ugly, that matures into a magnificent swan.