Nanjing vs Nanking

Nanjing and Nanking both are nouns.

Word	Noun	Adjective	Verb	Adverb
Nanjing	Yes	No	No	No
Nanking	Yes	No	No	No

As nouns, Nanjing and Nanking are synonyms defined as:

Nanjing and Nanking: a city in eastern China on the Yangtze River; a former capital of China; the scene of a Japanese massacre in the 1930s

Nanjing (noun)	Nanking (noun)
a city in eastern China on the Yangtze River; a former capital of China; the scene of a Japanese massacre in the 1930s	a city in eastern China on the Yangtze River; a former capital of China; the scene of a Japanese massacre in the 1930s