This is the 7853rd most frequent Japanese word.
喜明
"喜明" is a Japanese given name, typically meaning "joy" (喜) and "bright" or "clear" (明).
In this sentence, '喜明' is used as a proper noun to refer to a person by name.
喜明さんは親切な人です。
Mr. Kimei is a kind person.
In this case, '喜明' is being referred to as a name in general, discussing its uniqueness.
喜明という名前は珍しいです。
The name Kimei is unusual.
Here, '喜明' is used to denote the given name of an individual.