ugly duckling noun
plural ∼ -lings [count] : a person or thing that is not attractive or successful but that is likely to become attractive or successful in the future
▪ The house is an ugly duckling, but it has a lot of potential. ▪ an ugly duckling that has become a beautiful swan [=an ugly/unsuccessful person or thing that has become beautiful/successful]
▪ The house is an ugly duckling, but it has a lot of potential. ▪ an ugly duckling that has become a beautiful swan [=an ugly/unsuccessful person or thing that has become beautiful/successful]
