The most common and most likely answer to this crossword clue is the 10 letter word NON-LETHAL
I've seen this crossword clue in The Times
N
O
N
-
L
E
T
H
A
L
Buddy explains!
The straight part
We know that "It’s not going to kill anyone" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case it’s not going to kill anyone = non-lethal.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.