The most common and most likely answer to this crossword clue is the 4 plus 5 letter word EASY GOING
I've seen this crossword clue in The Daily Telegraph
E
A
S
Y
G
O
I
N
G
Buddy explains!
The straight part
We know that "Calm/painless death" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case calm/painless death = easy going.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.
Crossword Answer definitions
EASY GOING adjective- (of a person) calm, relaxed, casual and informal
- (of a journey or pace) unhurried