Dread blowing top, making mistake (5)
I believe the answer is:
error
'mistake' is the definition.
(synonyms)
'dread blowing top' is the wordplay.
'dread' becomes 'terror' (I've seen this in another clue).
'blowing top' means to remove the first letter.
'terror' with its initial letter removed is 'ERROR'.
'making' is the link.
(Other definitions for error that I've seen before include "Faux pas" , "Trial and ___" , "heresy" , "wrongdoing" , "Mistake or fault" .)