The most common and most likely answer to this crossword clue is the 6 letter word SALAAM
I've seen this crossword clue in The Times
S
A
L
A
A
M
More clues leading to the result SALAAM
- Threat to aircraft that’s coming across in style of greeting
- Greeting upset mother unfortunately
- Reverence for Muslims sadly rejected by leaders in America?
- I regret returning a mobster’s first greeting
- Old lady unfortunately rejected greeting
- Respectful gesture as second warning may be heard
- Old lady sadly returned greeting
- 9 healthy meals daughter’s abandoned for a month
- Greeting mother, sadly upset
- Greeting sadly returned in the morning
Buddy explains!

The straight part
We know that "greeting" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case greeting = salaam.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 SALAAM mean?
SALAAM noun- A low bow as a ceremonial act of deference.
- To perform a salaam (to someone).
- A respectful ceremonial greeting performed mostly in Islamic countries.