noun
explainer; expositor; elucidator
A person who explains or expounds something, often in a formal or instructional context. Less common than 説明する人 in everyday speech.
彼は新しい政策の説明者として記者会見に臨んだ。
He faced the press conference as the explainer of the new policy.
解説者 is a commentator or analyst who provides detailed commentary, often in media or sports, whereas 説明者 is a more general explainer.
Compound of 説明 (explanation) + 者 (person). A straightforward Sino-Japanese agent noun.