Dictionary.com
Thesaurus.com
Synonyms

arduous

American  
[ahr-joo-uhs, ahr-dyoo-] / ˈɑr dʒu əs, ˈɑr dju- /

adjective

  1. requiring great exertion; laborious; difficult.

    an arduous undertaking.

    Synonyms:
    exhausting, burdensome, wearisome, onerous, toilsome, hard
    Antonyms:
    easy
  2. requiring or using much energy and vigor; strenuous.

    making an arduous effort.

  3. hard to climb; steep.

    an arduous path up the hill.

  4. hard to endure; full of hardships; severe.

    an arduous winter.


arduous British  
/ ˈɑːdjʊəs /

adjective

  1. requiring great physical or mental effort; difficult to accomplish; strenuous

  2. hard to endure; harsh

    arduous conditions

  3. hard to overcome or surmount; steep or difficult

    an arduous track

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Other Word Forms

Etymology

Origin of arduous

First recorded in 1530–40; from Latin arduus “erect, laborious, steep”

Explanation

Use the adjective arduous to describe an activity that takes a lot of effort. Writing all those college essays and filling out the applications is an arduous process! Arduous was first used in English to mean "steep" or "difficult to climb." If you're an outdoorsman, hiking up a mountain is a lot of fun, but if you're a couch potato, it's an arduous trek. Today, the word can be used figuratively for something that is difficult or takes a lot of work. If you spend an arduous week studying for your final exams, you'll do well because you've worked really hard!

Keep Reading on Vocabulary.com

Vocabulary lists containing arduous

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.

See Examples For:

It was the last chance to pack supplies before the route’s most arduous section, and the first oasis one saw on the way back.

From The Wall Street Journal Jul. 31, 2026

“It was a long and arduous process for Peacock to reach profitability, and this is obviously a very important step for their business, but one small step in a much larger journey,” Katz said.

From Los Angeles Times Jul. 23, 2026

Seaweed foraging on the rocky coastline at the edge of the Pacific Ocean can be arduous and dangerous, says Wu, whose passion has kept her going for more than half a century.

From Barron's Jun. 30, 2026

"It'll be a historic day and the perfect end to a long arduous trip for the Tartan Army."

From BBC Jun. 24, 2026

There’s also a very practical reason for clambering up and down mountains, or doing anything arduous and unglamorous, what PIH-ers called “scut work.”

From "Mountains Beyond Mountains" by Tracy Kidder and Michael French

Vocabulary.com logo
by dictionary.com

Dictionary.com's Learning Companion

Go beyond just looking up words.
Remember them forever with VocabTrainer.

Start training