noun
expert; authority; well-versed person
Refers to someone deeply knowledgeable or skilled in a particular field. Often used with 〜の精通者 or 〜に精通している人.
彼はIT分野の精通者だ。
He is an expert in the IT field.
この問題については、法律の精通者に相談したほうがいい。
Regarding this issue, you should consult an authority on law.
達人 implies mastery through long practice, often in arts or skills. 精通者 focuses on comprehensive knowledge rather than practiced skill.
Compound of 精通 (せいつう, 'being well-versed') + 者 (しゃ, 'person'). The exact historical derivation is uncertain, but the word follows a common Sino-Japanese pattern for forming agent nouns.