The most common and most likely answer to this crossword clue is the 5 letter word ROPER
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More clues leading to the result ROPER
Buddy explains!

The straight part
We know that "that this person might find useful" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case that this person might find useful = roper.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does ROPER mean?
ROPER noun- An accomplice who locates a mark to be swindled by a confidence trickster.
- Agent noun of rope; one who uses a rope, especially one who throws a lariat or lasso.
- A maker of ropes.
- One who ropes goods; a packer.
- A crafty fellow; one fit to be hanged.
- A person hired by a gambling establishment to locate potential customers and bring them in.