Rad is informal slang meaning exciting, impressive, or cool. A skate trick, a new song, a jacket: That's rad.

Rad這個字 is是 informal slang一個非正式俚語，meaning意思是 exciting令人興奮的、impressive令人印象深刻的、or或 cool很酷的。A skate trick一個滑板招式、a new song一首新歌、a jacket一件夾克：that's rad這就是rad。

It is a shortened form of radical in the old youth sense — not radical as in politics, but radical as in extreme, awesome. It belongs to American surf, skate, and teen talk from the 1980s and 1990s.

It它 is是 a shortened form of radical radical的縮寫 in在 the old youth sense舊式青少年用法裡 — not不是 radical as in politics政治上的radical，but而是 radical as in extreme, awesome指極端、超讚的radical。It它 belongs to屬於 from the 1980s and 1990s一九八零、九零年代 American surf, skate, and teen talk美國衝浪、滑板和青少年用語。

Though actually, for a lot of young people now it sounds dated, like a film putting the eighties in someone's mouth. People still say it, sometimes sincerely, often with a smile. It is very casual.

Though actually不過其實, for a lot of young people now對現在很多年輕人來說 it它 sounds dated聽起來很過時, like a film putting the eighties in someone's mouth就像電影硬要角色講出八零年代的台詞一樣。People still say it還是有人會說, sometimes sincerely有時候是真心的, often with a smile常常帶著微笑。It它 is很 very casual口語。

Do not put it in a school essay unless you are quoting.

Unless you are quoting除非是引用, do not put it in a school essay不要把它用在學校作文裡。

A different rad is a unit used in radiation; that is not this word.

A different rad另一個rad is是 a unit used in radiation輻射用的單位; that is not this word那不是這個字。