1. Satisfied with the current situation and unconcerned with changing it, often to the point of smugness: "a geologic cautionary tale for a complacent world accustomed to reliable infusions of cheap energy" (Paul Roberts).
2. Eager to please; complaisant.
[Latin complacēns, complacent-, present participle of complacēre, to please : com-, intensive pref.; see COM- + placēre, to please; see plāk-1 in the Appendix of Indo-European roots.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2019 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.