Frightening people consequently turning on head of security (5)
I believe the answer is:
ogres
'frightening people' is the definition.
The definition and answer can be both people as well as being plural nouns.
Perhaps you can see a link between them that I don't see?
'consequently turning on head of security' is the wordplay.
'consequently turning' becomes 'og' (I can't justify this - if you can you should give a lot more credence to this answer).
'on' becomes 're' ('on' can be mean 'with reference to').
'head of' indicates taking the first letters.
The first letter of 'security' is 's'.
'og'+'re'+'s'='OGRES'
Can you help me to learn more?
(Other definitions for ogres that I've seen before include "Giants in fairytales" , "Beasts" , "Monstrous giants and man-eaters" , "Fairytale giants" , "'Monsters, fiends (5)'" .)