Marked by persevering, painstaking effort.
[Middle English, from Old French, from Latin dīligēns, dīligent-, present participle of dīligere, to esteem, love : dī-, dis-, apart; see DIS- + legere, to choose; see leg- in the Appendix of Indo-European roots.]
Synonyms: diligent, industrious, conscientious, assiduous, sedulous
These adjectives suggest steady attention and effort that is undertaken to accomplish something. Diligent connotes steady, meticulous attention to an ongoing job or task: "[They] have won international renown for their diligent efforts to track down software bugs" (Hiawatha Bray).
Industrious implies energetic and productive application, often to a large or important endeavor: "Madison's and Jefferson's vision of an agrarian republic made up largely of industrious farmers who marketed their burgeoning surpluses abroad" (Drew R. McCoy).
Conscientious carries with it the implication of energetic attentiveness springing from dutifulness or a sense of responsibility: "a studious, conscientious public servant authentically dedicated to improving the welfare of his fellow human beings" (Randall Bennett Woods).
Assiduous and the less common sedulous emphasize untiring exertion and an earnestness of purpose: "How do Olympians acquire [talent]? Were they born with it, or did they develop it through assiduous practice?" (Steve Olson). "the sedulous pursuit of legal and moral principles" (Ernest van den Haag).
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.