“Is there another word for synonym?”

Source: Vanishing Acts

Variant: Alone. Yes, that’s the key word, the most awful word in the English tongue. Murder doesn’t hold a candle to it and hell is only a poor synonym…
Source: 'Salem's Lot

p, 125
Man a Machine (1747)

Source: Ready Player One

Source: The Passing of an Illusion, The Idea of Communism in the Twentieth Century (1999), p. 4

On Pantheism as quoted in Faiths of Famous Men in Their Own Words (1900) by John Kenyon Kilbourn; also in Religion: A Dialogue and Other Essays (2007), p. 40
Essays

Source: The Lost Symbol: (Robert Langdon Book 3) https://books.google.nl/books?id=s8l5ApOH2CwC&printsec=frontcover&dq=%22dan+brown%22+%22the+lost+symbol%22&hl=nl&sa=X&ved=0ahUKEwjhmZ-Mia3MAhXLfRoKHXEnBN0Q6AEIKTAC#v=onepage&q=%22synonym%20for%20research%22&f=false, 2009, p. 98

Source: Intercourse (1987), Chapter 7
Context: A woman has a body that is penetrated in intercourse: permeable, its corporeal solidness a lie. The discourse of male truth—literature, science, philosophy, pornography—calls that penetration violation. This it does with some consistency and some confidence. Violation is a synonym for intercourse. At the same time, the penetration is taken to be a use, not an abuse; a normal use; it is appropriate to enter her, to push into ("violate") the boundaries of her body. She is human, of course, but by a standard that does not include physical privacy.

Source: He's Just Not That Into You: The No-Excuses Truth to Understanding Guys