Threaten mischievous child with death (6)
I believe the answer is:
impend
'threaten' is the definition.
(I've seen this before)
'mischievous child with death' is the wordplay.
'mischievous child' becomes 'imp' (imp can mean a misbehaving child).
'with' is a charade indicator (letters next to each other).
'death' becomes 'end' (synonyms).
'imp'+'end'='IMPEND'
(Other definitions for impend that I've seen before include "(Of a bad thing) loom" , "Be imminent or about to happen" , "appearing to be imminent" , "seen to be around the corner" , "Threaten; approach" .)