Free camping apparently a deterrent (7)
I believe the answer is:
trident
'a deterrent' is the definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.
'free camping apparently' is the wordplay.
I cannot quite see how this works, but
'free' could be 'rid' (to be free of something is to be rid of it) and 'rid' is located in the answer.
'camping' could be 'tent' (I've seen this in other clues) and 'tent' is present in the leftover letters.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for trident that I've seen before include "Britannia's weapon" , "Neptune's fork" , "Neptune's weapon" , "Neptune's or Britannia's spear" , "Three-pronged weapon" .)