blud-gilt'-i-nes: Found in the King James Version only in Ps 51:14. The Revised Version (British and American) adds Ex 22:2-3; 1Sa 25:26,33. Eze 18:13 seems to indicate that the phrase does not necessarily signify bloodshed, but any grievous sin which, if it remains, will block God's favor to His land and people (compare De 21:8; Isa 1:15). Ps 51:1-19 is to be interpreted in this light.
⇒See the definition of bloodguiltiness in the KJV Dictionary