Clue: Novice? One missing out with exploitative type in pocket (7)
Answer: TROUSER
Explanation: Definition: pocket
 "tiro"(or "tyro"/a novice or beginner) **minus**(… missing out) "I"(Roman numeral for "one") **plus**(with) USER(an exploitative type/one taking advantage of others).
Defn: Slang for …/to take or receive dishonestly.