A threat to people above one (6)
I believe the answer is:
menace
'a threat' is the definition.
('menace' can be a synonym of 'threat')
'people above one' is the wordplay.
'people' becomes 'men' (man is a kind of person).
'above' says to put letters next to each other.
'one' becomes 'ace' ('ace' can be a synonym of 'one').
'men'+'ace'='MENACE'
'to' acts as a link.
(Other definitions for menace that I've seen before include "Act in a threatening manner" , "Threaten with violence" , "Threat; threaten" , "Threat, show of hostility" , "Intimidate" .)