Her narcissistic personality makes her always talk about her own achievements, never caring about others' feelings.

narcissistic 是形容词，来自名词 narcissism（自恋）。这个词源自希腊神话中爱上自己水中倒影的美少年 Narcissus（那喀索斯），用来形容"过度自我欣赏、以自我为中心"的性格特征。narcissistic personality 指"自恋型人格"，表现为过度关注自我、缺乏同理心。