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 goodness that I've seen before include "Virtue, rightness" , "Virtue; excellence" , "Morality, generosity, kindness" , "Boy" , "Moral excellence" .)