The Gemara challenges: But wherever there is liability for capital punishment, this tanna teaches it; as it is taught in the first clause: With regard to bloodshed, if a gentile murders another gentile, or a gentile murders a Jew, he is liable. If a Jew murders a gentile, he is exempt. Evidently, the term liable is used in the baraita. (Sanhedrin 57a)
What is the meaning of these words?