ビシバシ

adverb, adverb taking the 'to' particle

without holding back; mercilessly; relentlessly; vigorously

Describes doing something forcefully, relentlessly, or without restraint, often with a sense of strictness or intensity. Can be used for scolding, training, working, or criticizing.

• 上じょう司しにビシバシしごかれた。

  I was trained relentlessly by my boss.

• 彼かれは生せい徒とをビシバシ叱しかる。

  He scolds his students without holding back.