'Blood guiltiness' in the Bible

Now therefore, my lord, as Jehovah liveth, and as thy soul liveth, seeing Jehovah hath withholden thee from bloodguiltiness, and from avenging thyself with thine own hand, now therefore let thine enemies, and them that seek evil to my lord, be as Nabal.

and blessed be thy discretion, and blessed be thou, that hast kept me this day from bloodguiltiness, and from avenging myself with mine own hand.