ugly duckling
US /ˈʌɡ.li ˈdʌk.lɪŋ/
UK /ˈʌɡ.li ˈdʌk.lɪŋ/

1.
гадкий утенок
a person or thing that is initially unattractive or unpromising but eventually becomes beautiful or successful
:
•
She was an ugly duckling in high school, but she grew up to be a stunning model.
Она была гадким утенком в старшей школе, но выросла в потрясающую модель.
•
The old building was considered an ugly duckling, but after renovation, it became the most beautiful one in the city.
Старое здание считалось гадким утенком, но после реконструкции оно стало самым красивым в городе.