idiosyncrasy
/ˌɪdɪəˈsɪŋkrəsɪ; ˌɪdɪə`sɪŋkrəsɪ/ n
person's particular way of thinking, behaving, etc that is clearly different from that of others （个人独有的）习性、 癖好、 气质
One of her little idiosyncrasies is always washing in cold water. 她有个怪习惯, 就是洗什麽都爱用冷水.