Old god in charge of consternation (5)
I believe the answer is:
panic
'consternation' is the definition.
(I've seen this before)
'old god in charge' is the wordplay.
'old god' becomes 'pan' (Pan is a Greek god. I am not sure about the 'old' bit.).
'in charge' becomes 'ic' (abbreviation for 'in charge').
'pan'+'ic'='PANIC'
'of' acts as a link.
Can you help me to learn more?
(Other definitions for panic that I've seen before include "displaying great fear" , "Losing one's head" , "Sudden overpowering anxiety" , "Overwhelming terror" , "Sudden extreme anxiety" .)