unprepossessing
US /ˌʌn.priː.pəˈzes.ɪŋ/
UK /ˌʌn.priː.pəˈzes.ɪŋ/

1.
poco atractivo, desagradable
not attractive or appealing to the eye
:
•
The old house was rather unprepossessing from the outside.
La casa antigua era bastante poco atractiva por fuera.
•
Despite his unprepossessing appearance, he was a brilliant scientist.
A pesar de su apariencia poco atractiva, era un científico brillante.