Security, if following debt collector (7)
I believe the answer is:
bailiff
'debt collector' is the definition.
The answer and definition can be both people as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'security if following' is the wordplay.
'security' becomes 'bail' (I've seen this before).
'following' becomes 'f.' (used when citing page numbers etc).
'bail'+'if'+'f'='BAILIFF'
Can you help me to learn more?
(Other definitions for bailiff that I've seen before include "Landlord's agent or steward" , "Court official" , "Officer of court" , "Law officer who helps sheriff, say to foreclose" , "Possibly menacing landlord's agent" .)