Pronounce not guilty of criminal charges (6)
I believe the answer is:
acquit
'pronounce not guilty of criminal charges' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for acquit that I've seen before include "Pronounce not guilty of criminal charges" , "Clear of a crime" , "Declare to be innocent of a crime" , "Exonerate" , "Group of families" .)