These are a few of the examples of traditional Chinese idiomatic expressions which are generally represented by four letters and give an insight into the richness of language. Of course, the list of expressions is practically a never-ending sea of intricate layers of literature having their links to various eras.
花容月貌
the appearances of a flower, face like the moon
The literal meaning of this idiom is the countenance of a flower, face like the moon and figuratively it is used by writers and speakers to describe a woman who is utterly beautiful. It is a positive idiom that exemplifies the appearance of a woman and how she is as tender as a bloomed flower and face as pristine as a marbled colored moon on a clear night.
梨花带雨
the tear-stained face of a beauty
The idiom originated from two famous lines in The Song of Everlasting Regret (长恨歌), loneliness appeared on her pretty face with tear stain, like a blossom on a pear tree after a spring rain.
沉鱼落雁
makes the fish sink and wild geese fall
(of feminine beauty) be striking enough to make fish sink and birds alight - be extremely beautiful; have looks that outshine the moon and put the flowers to shame.
闭月羞花
a beauty which would obscure the moon and make flowers blush
(of a young woman's beauty) make the moon hide behind a cloud and put the flowers to shame - be bewitchingly beautiful.
窈窕淑女
the gentle and graceful young woman
Another idiom featuring in the positive spectrum of the language, yǎo tiǎo shū nǚ is one of the well-known phrases in Chinese culture which means gentle and graceful woman. It generally describes the way a lady carries herself and delves deeper into the ingrained characteristics of a female rather than presenting merely an outward appearance. It is taken from the Book of Songs · Zhou Nan · Guan Yan.
桃腮杏眼
rosy cheeks and almond eyes - fair feminine faces
Sourced from the third round of "Ping Gui Biography", this idiom has literal meaning- rosy cheeks and almond eyes. Since a writer inherits a sort of free reign with words while expressing his/her mind, this phrase has been loosely used to describe something attractive and eye-catching generally in the context of a woman.