The most common and most likely answer to this crossword clue is the 5 letter word TELOS
I've seen this crossword clue in The Guardian
T
E
L
O
S
More clues leading to the result TELOS
Buddy explains!

The straight part
We know that "End" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case end = telos.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 TELOS mean?
TELOS noun- The aim or goal.