The most common and most likely answer to this crossword clue is the 11 letter word ENFORCEMENT
I've seen this crossword clue in The Guardian
E
N
F
O
R
C
E
M
E
N
T
More clues leading to the result ENFORCEMENT
Buddy explains!

The straight part
We know that "application" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case application = enforcement.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 ENFORCEMENT mean?
ENFORCEMENT noun- The act of enforcing; compulsion.
- A giving force to; a putting in execution.
- That which enforces, constraints, gives force, authority, or effect to; constraint; force applied.