傲嬌
ào jiāo
Originated from the Japanese gaming and manga/anime sub-culture, “tsundere” [ツンデレ] describes a person who is initially cold and even hostile towards another person before gradually showing their warm and even coy side over time. Now the term is also used to mean “sassy”.
A partner phrase with this that is also commonly found in the online sphere is 撒嬌 （sa jiao) which means to be sassy in a feminine way or a cute way. Usually done to guys by a girl in an affectionate way.