The most common and most likely answer to this crossword clue is the 12 letter word CIRCUMSCRIBE
I've seen this crossword clue in The Daily Telegraph
C
I
R
C
U
M
S
C
R
I
B
E
Buddy explains!

The straight part
We know that "Limit" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case limit = circumscribe.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 CIRCUMSCRIBE mean?
CIRCUMSCRIBE verb- To draw a line around; to encircle.
- To limit narrowly; to restrict.
- To draw the smallest circle or higher-dimensional sphere that has (a polyhedron, polygon, etc.) in its interior.