The most common and most likely answer to this crossword clue is the 7 letter word WHEELER
I've seen this crossword clue in The Daily Telegraph
W
H
E
E
L
E
R
More clues leading to the result WHEELER
Buddy explains!

The straight part
We know that "manipulative practices" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case manipulative practices = wheeler.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 WHEELER mean?
WHEELER noun- A wheelwright, a wheelmaker.
- Someone who operates a wheel.
- A wheelhorse (horse near wheel of carriage).
- (used in combination with a preceding whole number) A vehicle having the specified number of wheels.