Detective and soldier wearing item of clothing next to one reptile (7,12)
I believe the answer is:
private investigator
'detective and soldier wearing item of clothing next to one reptile' is the definition.
I can't judge whether this definition defines the answer.
'detective and soldier wearing item' is the wordplay.
'detective' becomes 'investigator' (synonyms).
'and' says to put letters next to each other.
'soldier wearing item' becomes 'private' (I am not sure about this - if you are sure you should believe this answer much more).
'investigator' put after 'private' is 'PRIVATE INVESTIGATOR'.
Can you help me to learn more?
(Other definitions for private investigator that I've seen before include "Dick" , "Sleuth" , "Freelance detective" , "one makes enquiries" .)