The most common and most likely answer to this crossword clue is the 9 letter word EMOLLIENT
I've seen this crossword clue in The Times
E
M
O
L
L
I
E
N
T
More clues leading to the result EMOLLIENT
- Soothing molten rocks? There’s falsity in that!
- Calming English gang girl that is not without heart
- Assuasive English gang girl that is not without heart
- Soothing heart of fellow, time one loosened bandages
- Relieving girl in hospital department
- Making soft pork pie in Melton? That’s unusual
- Soothing girlfriend of gangster that is found in e-books
- Lie mole made up to National Trust to get cream
- Sam, maybe, in book brought up as conciliatory
- Rambling on – tell me I must be soothing!
Buddy explains!

The straight part
We know that "Calming" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case calming = emollient.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 EMOLLIENT mean?
EMOLLIENT noun- Something which softens or lubricates the skin; moisturizer.
- Anything soothing the mind, or that makes something more acceptable.
- Moisturizing.
- Soothing or mollifying.