NET

21 or with enmity he strikes him with his hand and he dies, the one who struck him must surely be put to death, for he is a murderer. The avenger of blood must kill the murderer when he meets him.

Darby

21 or from enmity smite him with his hand, so that he die, he that smote him shall certainly be put to death; he is a murderer: the avenger of blood shall put the murderer to death, when he meeteth him.

KJV

21 Or in enmity smite him with his hand, that he die: he that smote [him] shall surely be put to death; [for] he [is] a murderer: the revenger of blood shall slay the murderer, when he meeteth him.