The most common and most likely answer to this crossword clue is the 7 letter word APPEASE
I've seen this crossword clue in Financial Times
A
P
P
E
A
S
E
More clues leading to the result APPEASE
- Software to facilitate calm
- Seeds eaten by parrot satisfy
- Pacify a gorilla, say, eating small vegetables
- Placate monkey, feeding it vegetables
- Placate gorilla, say, feeding him vegetables
- Calm, primate eating green seeds
- Computer program to facilitate calm
- Short ring of bells in part of church – or quiet
- Placate primate hoarding vegetables
- Calm primate eats seeds
Buddy explains!

The straight part
We know that "calm" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case calm = appease.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 APPEASE mean?
APPEASE verb- To make quiet; to calm; to reduce to a state of peace; to dispel (anger or hatred).
- To come to terms with; to adapt to the demands of.