We are under a feeling of wonder (3)
I believe the answer is:
awe
'feeling of wonder' is the definition.
(awe is a feeling of wonder or fear)
'we are under a' is the wordplay.
'are under' is a charade indicator (letters next to each other) (below, in a down clue).
'we' after 'a' is 'AWE'.
(Other definitions for awe that I've seen before include "alarm" , "Amazed wonder" , "Fear - veneration" , "Reverential wonder" , "(Strike with) reverential fear" .)