Fear of terrible pain and a tragic end (5)
I believe the answer is:
panic
'fear' is the definition.
(I know that panic is a more specific form of the action fear)
'terrible pain and a tragic end' is the wordplay.
'terrible' indicates anagramming the letters.
'and' means one lot of letters go next to another.
'end' suggests the final letters.
The final letter of 'tragic' is 'c'.
'pain' is an anagram of 'pani'.
'pani'+'c'='PANIC'
'of' is the link.
(Other definitions for panic that I've seen before include "Widespread fear" , "Sudden overpowering fear" , "Sudden uncontrollable fear" , "Go to pieces" , "Lose the head, yield to fear" .)