事情通(じじょうつう)having good knowledge of a certain matter, person who has good knowledge of a certain matter, informed source

事情(じじょう)通(つう)の同僚(どうりょう)は何(なん)でもよく知(し)っています。

My colleague who is an informed source knows everything very well. {having good knowledge of a certain matter, person who has good knowledge of a certain matter, informed source}

また事情(じじょう)通(つう)の友達(ともだち)から学校(がっこう)内(ない)の噂(うわさ)について聞(き)きました。

I heard about the rumors within the school from a friend who is an informed source. {having good knowledge of a certain matter, person who has good knowledge of a certain matter, informed source}

事情(じじょう)通(つう)の彼女(かのじょ)はどうやって色々(いろいろ)な情報(じょうほう)を得(え)ているのだろう？

How does she, who is an informed source, obtain various information? {having good knowledge of a certain matter, person who has good knowledge of a certain matter, informed source}

僕(ぼく)は事情(じじょう)通(つう)で、クラスメイトの交友(こうゆう)関係(かんけい)なども全(すべ)て把握(はあく)している。

I am well-informed, and I have a good understanding of all of my classmates' social relationships. {having good knowledge of a certain matter, person who has good knowledge of a certain matter, informed source}

僕(ぼく)は事情(じじょう)通(つう)なチームメイトに僕(ぼく)の私生活(しせいかつ)を知(し)られないようにしています。

I am trying to keep my personal life unknown to my teammates who have good knowledge of certain matters. {having good knowledge of a certain matter, person who has good knowledge of a certain matter, informed source}