The Arabic word for moon can be a blushing compliment just as much as it can denote an empty promise or an impossible request.
The Moon, in Arabic, is qamar. The word is also used as a name. Although it's a bit dated, to say someone is like the Moon — mitl al qamar — is to say they are exceptionally beautiful.
Another variation of this is qamar arbaatash, a reference to the 14th day of the lunar month, the day of the full moon (badr). The crescent, meanwhile, is hilal. Hilal mutazayid is a waxing crescent. Hilal akhir asshahr is a waning one. Alahdub almutazayid is a waxing gibbous moon. Alahdub almutanaqis is a waning gibbous. The Moon at the first quarter can be referred to as al tarbea al awwal, whereas al tarbea al thani is in its second quarter.
On that note, the lunar month is asshar al qamari. In plural that would be, asshuhoor alqamariyya. Alsine alqamariyya is the lunar year.
In dual form, al qamaraanm is a way to refer to the Sun (al shams) and the Moon. Al qamar is also the 54th chapter of the Quran.
Qamar sinaai, literally translating to artificial moon, means satellite.
Qamar al din is an apricot fruit leather that’s made into a nectar beverage that is traditionally most consumed during the holy month of Ramadan.
To say someone is asking for the Moon — aam titlob al qamar — is to say they are asking for the impossible. To say they promised the Moon — waaada bilqamar — is to say they promised something they are unable to fulfil.
If someone has aadat al qamar, or the habits of the Moon, it means they’re usually asleep during the day and out at night.
The Moon has a prevalent place in Arabic music.
Fairuz, in particular, has a handful of songs that make use of the Moon’s symbolism, including Balleghouhou Ya Qamarou (Let him know, oh Moon) and Ya Qamar Ala Daretna (Oh Moon, on our house).
Melhem Barakat also has a song titled Amarein (Two moons). Amr Diab’s 1999 hit album and song are also titled the same.
One of Mahmoud Darwish’s most famous lines of poetry puts into question the Moon’s beauty, saying: Larubbama al qamar laysa jameelan illa liannahu baaeed. “Maybe the Moon isn’t beautiful but maybe only distant.”