Hooray! (5)
(Other definitions for whoopee that I've seen before include "that delights me" , "I'm so happy!" , "Love" , "Hooray!" , "exclamation of joy" .)
(Other definitions for bravo that I've seen before include "Theatrical 'well done'" , "Radio code word for B" , "Expression of approval" , "International Call Sign: appreciation shown at the opera" , "Well done; B (radio)" .)
(Other definitions for yeah that I've seen before include "Indeed" , "Yes (informally)" , "OK" , "Sure!" , "Surely" .)
'hooray' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for yippee that I've seen before include "That's wonderful!" , "Cry of excitement" , "Exclamation of wild delight (colloq.)" , "I'm deliriously happy!" , "An exclamation of excitement or enthusiasm" .)