A1 unhappy or sorry伤心的，悲哀的；令人难过的，令人遗憾的
informal If something looks sad, it looks worse than it should because it is not being cared for.可怜的，凄惨的
We said our sad farewells and got on the bus.
I don't feel angry so much as sad.
That was such a sad film.
I just felt sad for her.
I was very sad when our cat died.
[ before noun ] not satisfactory or pleasant令人遗憾的；令人不快的
C1 something you say when you are telling someone about something bad that happened真遗憾，可惜的是
slang showing that you are not fashionable or interesting or have no friends老土的；乏味的；不受欢迎的
abbreviation for seasonal affective disorder: a medical condition in which a person does not have much energy and enthusiasm during the winter because of the reduced period of natural light季节性不适（冬季因日照时间缩短而引发的精力不济，seasonal affective disorder的缩写）