file out：出ていく

Defending Jacob.83%読了

”An educated guess, yes."
educated guess (知識、経験に基づく）推測

HIs job here was to say as little as possible, to pare away every extra word.
pare away:削り取る
pare：a(ナイフで)〈果物・ジャガイモなどの〉皮をむく 《★【類語】 peel はオレンジ・バナナなどの皮を手でむく》.

Detective Duffy, you say you have no reservations at all about the way Andrew Barber conducted this case?
have no reservations about:～に対する不安［危ぐ・ためらい］は何もない

The jury filed out, exchanging looks with each other.
file out:でていく

To deflect any inference of guilt from the actual knife he owned?
deflect:そらす

The driver relented, though.
relent:(怒り・興奮などが少しやわらいで)穏やかな気持ちになる、ふびんに思うようになる、弱まる、やわらぐ

"hi"Jacob said, constrained by manners and habit from expressing any sense of anger or betrayal.
constrain〈人に〉強いて[無理に]〈…〉させる 〈to do〉《★しばしば受身で用いる》.
My conscience constrained me to apologize to him. 良心の呵責(かしやく)に堪えかねて彼に謝罪した.

Must be somebody who's got a geef with Jacob.
have a beef with 〈俗〉～に文句［不満・苦情］がある -