This word was derived from both middle english and contemporary jive talk. The -thu comes from the old "thou" which is, of course, "you". The -rr is added in modern english to complete the word. Altogether the word "thurr" means "I like your place right there", referring to a specific body part, usually the abdominal area of a female.
Brought to public attention by Bob Woodward and Carl Bernstein in the book on the fall of Richard Nixon, All The President’s Men, ratfucker was Nixon’s term for a political operative who sows chaos among opponents; an agent provocateur. It is thought to have originated among campus political rivalries at USC, and seems to have some usage in the US military.
Along with Nixon’s other ratfuckers, Roger Stone caused fights at otherwise peaceful Democratic Party protests to generate a false narrative that the Democrats were violent and dangerous.