“integrity.” Or, “uprightness,” but in this case, a person who lives in uprightness lives in integrity.
“shows contempt for him.” This is an example of how words or phrases like “despise,” “show contempt,” and “hate,” can have a range of meaning from active hostility to neglecting and ignoring. Verses like this are why the wise person looks at how a person acts to determine where they stand with God. Jesus taught us that we will recognize people by their fruit, not by what they say (Matt. 7:16, 20). Ungodly people are liars. Also, much of the time ungodly people are so self-deceived that they do not even know they are wrong in what they say. The wise and godly person knows the Word of God well enough that he knows what loving and fearing God looks like, and is not fooled by someone who says they love God but by their actions declare they actually neglect, ignore, or even despise God.