1. Having or marked by repeated turns or bends; winding or twisting: a tortuous road through the mountains.
2. Not straightforward; circuitous; devious: a tortuous plot; tortuous reasoning.
3. Highly involved; complex: tortuous legal procedures.
[Middle English, from Anglo-Norman, from Latin tortuōsus, from tortus, a twisting, from past participle of torquēre, to twist; see terkw- in the Appendix of Indo-European roots.]
Usage Note: Although tortuous and torturous both come from the Latin word torquēre, "to twist," their primary meanings are distinct. Tortuous means "twisting" (a tortuous road) or by extension "complex" or "devious." Torturous refers primarily to torture and the pain associated with it. However, torturous also can be used in the sense of "twisted, strained, belabored" and tortured is an even stronger synonym: a tortured analogy.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.