assiduous
Americanadjective
-
constant in application or effort; working diligently at a task; persevering; industrious; meticulous.
an assiduous student.
- Antonyms:
- lazy, inconstant
-
assiduous reading.
- Synonyms:
- persistent, tireless, continuous
- Antonyms:
- lazy, inconstant
adjective
-
hard-working; persevering
an assiduous researcher
-
undertaken with perseverance and care
assiduous editing
Other Word Forms
- assiduously adverb
- assiduousness noun
- unassiduous adjective
- unassiduousness noun
Etymology
Origin of assiduous
First recorded in 1530–40; from Latin assiduus, equivalent to assid(ēre) “to sit near or beside, dwell close to” ( assess ) + -uus adjective suffix; -ous
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
The U.S. assessment attributed the escapes to mismanagement by Syria’s government and a lack of assiduous custody of the camp’s large security perimeter, the U.S. officials said.
From The Wall Street Journal • Feb. 20, 2026
Powell’s assiduous outreach to his colleagues gives him a good overview of where the proverbial bodies are buried, giving colleagues ample time to voice their objections.
From Barron's • Dec. 12, 2025
"Martyn is the most professional, assiduous, diligent police officer you will come across and he should never have been put in this position," he said.
From BBC • Oct. 22, 2024
Grindset impresario and assiduous podcast guest Scott Galloway loitered by the back bar.
From Slate • Aug. 21, 2024
“I stand corrected, my sweetling. Our Yunkish friends were kind enough to provide us with a chart. I must strive to be more assiduous about consulting it.”
From "A Dance with Dragons" by George R. R. Martin
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
