barrage of questions; grilling
Describes a situation where someone is relentlessly questioned, often in an overwhelming or aggressive manner.
The minister faced a barrage of questions at the press conference.
I was exhausted after being bombarded with questions by the kids all day.
攻め means 'attack' or 'offensive'; in compounds like 質問攻め it adds the sense of being under siege by something.
Compound of 質問 (question) and 攻め (attack), literally 'question attack'.