adj. knot·ti·er, knot·ti·est
1. Tied or snarled in knots.
2. Covered with knots or knobs; gnarled.
3. Difficult to understand or solve: "[The columnist] supplies funny, wise responses to knotty ethical dilemmas posed by readers" (David Pogue).
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2020 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.