Sentence:  Ryan′s natural father was a <WSD>cleanskin</WSD> – a police term for a person with no criminal history – who found himself caught up in the world of career criminals when he married into The Clan. 
Meaning of the word marked with <WSD> tags:  Someone with no prior criminal record, a person with no previous convictions; loosely, someone who has not done anything wrong before, an unblemished character.