Nagi (なぎ)

Nagi is the Japanese word that indicates the state of flat and stable condition and it is also an archaic word. The pronunciation of 'nagi' preceded and later, various Chinese characters were assigned to it.
As meaningful descriptions, nagi is also described as '和ぎ, 凪, 薙ぎ.'
As antonyms, '荒れ (are: roughness),' '波 (nami: waves)' and '起伏 (kifuku: ups and downs)' exist.

Summary
The differences of meaning when nagi is described as '和, 凪, 薙ぎ.'

和ぎ' means friendly and calm and is used mainly to describe the mentality and state or environment.

凪' has the similar meaning to '和ぎ,' but today it often describes the calm state of the sea without wind and waves. And the Chinese character used for '凪' is one of the few kokuji (Chinese characters invented in Japan) that describe the state that the wind has stopped.

薙ぎ (nagi)' describes the state that a mountain has collapsed and is being flattened, or a flat field where grass and trees have been cut off. And it also has a meaning of slashing something off horizontally. From this meaning, it came to mean the exorcisation and purification as a Shinto ritual. Also Shinto rituals of '薙' exist all over Japan, and it is considered a rite to calm down storms or strong winds in the inland areas. There is a unusual letter '𡵢 (nagi)' for it which is a phonetic-equivalent character that comes from the meaning of collapsing.

Many Chinese characters are used to describe 'nagi.'
Nagi is also often used to describe the homonyms of trees, mountains and place names. But the word nagi mostly indicates the things that are involved in Shinto and myths in Japan and the place of worship in the Ancient Shinto. And it is used as the part of the name of shrines and gods in Japan.

Hiromogi (a temporarily erected sacred space or "altar" used as a locus of worship)
Hiromogi is a yorishiro (object representative of a divine spirit) of trees, branches, or leaves. In the ancient time, rocks, mountains and huge trees were the objects of worship. Nowadays hiromogi often refers to the shinboku (sacred tree) and sakaki (species of evergreen sacred to Shinto) for ritual use. The rocks and mountains as yorishiro tend to be called iwakura (dwelling place of a god, usually in reference to a large rock).

Hiromogi is '南木 (nagi),' or '楠 (camphor tree),' and some shrines name it '南木 (nagi)' and enshrine it as shinboku.

It is also described as '梛, 那木, 竹柏 (nagi),' and it indicates trees called nagi. As the tree nagi is associated with '和ぎ (nagi: calmness), it is used as hiromogi (which means the branches and leaves as the yorishiro for Shinto rituals).

Hiromogi is '榊 (nagi) and it also indicates the sakaki (sacred tree of Shinto) which is called 'nagi.'
It is used as hiromogi.

Myths and shrines in Japan
Chinese characters such as 蕩, 諾, 名杵, 那岐, 那芸 are used to describe 'nagi' of 'Izanagi,' Awanagi,' 'Tsuranagi' and 'Naginami.'
In addition, there is a sword called Kusanagi no tsurugi, which is one of Sanshu no Jingi (Three Imperial Regalia) that 'Yamato Takeru' uses.

Nagi Shrine exists all over Japan, and it is described as below

梛神社 (Nagi-jinja Shrine)
諾神社 (Nagi-jinja Shrine)
那岐神社 (Nagi-jinja Shrine)
南木神社 (Nagi-jinja Shrine)
名木神社 (Nagi-jinja Shrine)

Name of the place
Besides the representation in Chinese characters mentioned above, many Chinese characters such as 奈義, 奈癸, 奈岐 and 名義, used to describe 'nagi,' and 'Nagi River' and 'Mt Nagi,' exist.