"What did you say?" (3)
'what did you say?' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for come again that I've seen before include "return invitation" , "I'm sorry?" , "You're welcome to return - pardon?" , "Turn out once more" , "What did you say? - egomaniac (anag)" .)
(Other definitions for pardon that I've seen before include "Forgive the polite interruption" , "Forgive; come again?" , "Forgive or remit" , "Excuse or absolve" , "Forgive - eh?" .)
'what did you say?' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for huh that I've seen before include "sorry?" , "Expression of disgust or surprise" , "Palindromic exclamation of disgust or surprise" .)