This is the 504th most frequent Vietnamese word.
xinh
"Xinh" means "pretty" or "cute."
The word 'xinh' is used to describe someone's appearance in a positive and pleasant way, equivalent to 'pretty' in English.
Cô ấy trông rất xinh khi mặc chiếc váy đó.
She looks very pretty wearing that dress.
Here, 'xinh' (part of 'xinh xắn') is used to describe an object (the painting) which is attractive or lovely in appearance.
Bức tranh này thật xinh xắn.
This painting is really charming.
In this context, 'xinh' is used to describe a specific feature (the smile) as being delightful or appealing.