Threatens to finish in bad spirits (7)
I believe the answer is:
impends
'threatens' is the definition.
(I've seen this before)
'finish in bad spirits' is the wordplay.
'finish' becomes 'end' (synonyms).
'in' is an insertion indicator.
'bad spirits' becomes 'imps' (I have seen 'Mischievous spirits ' mean 'imps' so perhaps 'spirits' could also mean 'imps'. I am not sure about the 'bad' bit.).
'end' put within 'imps' is 'IMPENDS'.
'to' is the link.
Can you help me to learn more?
(Other definitions for impends that I've seen before include "Approaches" , "Threatens" .)