The most common and most likely answer to this crossword clue is the 7 letter word PAROLEE
I've seen this crossword clue in The Guardian
P
A
R
O
L
E
E
More clues leading to the result PAROLEE
- I’m free! Triumphant expression in dock
- Prisoner who’s been released, having a function in gym
- Function assumed by wild ape, one freed with strings
- Quiet character in Casualty who has his sentence interrupted
- Offender who’s out taking a part in educational exercise
- Someone let out cheer, interrupting shave
- Probationer’s part in ape’s transformation
Buddy explains!

The straight part
We know that "one freed with strings" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case one freed with strings = parolee.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.