The most common and most likely answer to this crossword clue is the 14 letter word DEFENESTRATION
I've seen this crossword clue in The Times
D
E
F
E
N
E
S
T
R
A
T
I
O
N
Buddy explains!
The straight part
We know that "going out the window" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case going out the window = defenestration.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 DEFENESTRATION mean?
DEFENESTRATION noun- The act of throwing something or someone out of a window.
- The high-profile removal of a person from an organization.
- The act of removing the Microsoft Windows operating system from a computer in order to install an alternative one.