The most common and most likely answer to this crossword clue is the 7 letter word MANACLE
I've seen this crossword clue in The Times
M
A
N
A
C
L
E
More clues leading to the result MANACLE
- Fellow outside prison about to get mechanical restriction
- Staff given a hint: uniform is missing cuff
- Not all current No.1s are covered by, say, boy band
- Person with fancy lace cuff
- Guy carrying container of beer back in hamper
- Fellow with line in excellent restraint
- Awful name-calling Heather ignored, showing restraint
- Clap in irons a salt interrupting the person speaking
- Handcuff chap, adult, oddly calmed
- He is one having long shackle
Buddy explains!

The straight part
We know that "cuff" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case cuff = manacle.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 MANACLE mean?
MANACLE noun- A shackle for the wrist, usually consisting of a pair of joined rings; a handcuff; (by extension) a similar device put around an ankle to restrict free movement.
- A fetter, a restriction.
- To confine with manacles.