Expression of surprise (3)
'expression of surprise' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for gee that I've seen before include "Gracious" , "Urge horse - expression of surprise" , "provided by substitute for ginger?" , "Well I never" , "move faster" .)
(Other definitions for aha that I've seen before include "Palindromic exclamation of triumph or surprise" , "it expresses surprise" , "Exclamation of triumph or mockery, a palindrome" , "Cry of triumph" , "Triumphant cry" .)
(Other definitions for goodness that I've seen before include "Virtue, righteousness" , "Virtue; excellence" , "Virtue, rightness" , "Moral excellence" , "merit" .)
(Other definitions for crikey that I've seen before include "Gosh!" , "Good Lord!" , "Good heavens!" , "Cor blimey!" , "by George" .)