Man is entering name back to front (6)
I believe the answer is:
mister
'front' is the definition.
The definition and answer can be both people as well as being singular nouns.
Maybe there's an association between them I don't understand?
'man is entering name back' is the wordplay.
'man' becomes 'm' (M is an abbreviation for male or masculine).
'entering name' becomes 'ret' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'back' says the letters should be written in reverse.
'ret' written backwards gives 'ter'.
'm'+'is'+'ter'='MISTER'
'to' acts as a link.
Can you help me to learn more?
(Other definitions for mister that I've seen before include "Set rim (anag.)" , "Male form of address" , "that's what you'd call him" , "Form of address to a man, used without his name" , "Mr" .)