slap on the wristnnoun: Refers to person, place, thing, quality, etc.
figurative (mild reprimand)
轻微的惩罚 qīng wēi de chéng fá
Two years in prison was no more than a slap on the wrist for that revolting murderer. Philip needn't have worried about the sentence, as he was only given a slap on the wrist.