Definition of complexnext
1
as in facility
a structure that is designed and built for a particular purpose an apartment complex

Synonyms & Similar Words

2
as in system
something made up of many interdependent or related parts a complex of government programs designed to assist the needy

Synonyms & Similar Words

Synonym Chooser

How does the adjective complex differ from other similar words?

Some common synonyms of complex are complicated, intricate, involved, and knotty. While all these words mean "having confusingly interrelated parts," complex suggests the unavoidable result of a necessary combining and does not imply a fault or failure.

a complex recipe

When is complicated a more appropriate choice than complex?

While the synonyms complicated and complex are close in meaning, complicated applies to what offers great difficulty in understanding, solving, or explaining.

complicated legal procedures

When might intricate be a better fit than complex?

The synonyms intricate and complex are sometimes interchangeable, but intricate suggests such interlacing of parts as to make it nearly impossible to follow or grasp them separately.

an intricate web of deceit

When is it sensible to use involved instead of complex?

Although the words involved and complex have much in common, involved implies extreme complication and often disorder.

a rambling, involved explanation

When would knotty be a good substitute for complex?

While in some cases nearly identical to complex, knotty suggests complication and entanglement that make solution or understanding improbable.

knotty ethical questions

Example Sentences

Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Recent Examples of complex
Adjective
Higdon once had to pull a calf from the birth canal of its mother during a complex delivery. David Kelly, Los Angeles Times, 8 Aug. 2026 This is especially important for complex social experiences, which are only indirectly related to the genetic variants used as proxies. The Conversation Us, Scientific American, 8 Aug. 2026
Noun
On McCart Avenue east of campus, near Latta’s house, the townhome complex that’s under construction on a former parking lot site will have 120 units, available primarily to juniors and seniors. Matthew Adams, Fort Worth Star-Telegram, 13 Aug. 2026 Other businesses in the neighborhood near the Pullman Gateway complex that were recruited by Chicago Neighborhood Initiatives include Lexington Betty Smokehouse, a Potbelly sandwich shop and a Culver’s that opened in 2021. Brian J. Rogal, Chicago Tribune, 13 Aug. 2026 See All Example Sentences for complex
Recent Examples of Synonyms for complex
Adjective
  • Officials said deep peat soil, limited water supplies, difficult access and strong winds have complicated efforts, even with three helicopters conducting aerial firefighting operations.
    ABC News, ABC News, 10 Aug. 2026
  • When given a complicated test, AI models (the industry term for the systems behind products like ChatGPT and Claude) find a way to maximize the score without doing the task the score was meant to measure.
    Craig S. Smith, Forbes.com, 9 Aug. 2026
Adjective
  • The intricate diamond cuts and iconic Lismore pattern will cast elegant dapples of light across your table, while the weight of the crystal makes every clink feel even more satisfying.
    Mina Dragani, Architectural Digest, 14 Aug. 2026
  • The new era of gourmands celebrate the intricate connection between food, fragrance, and nostalgia in an elevated way.
    Danielle James, Vogue, 14 Aug. 2026
Noun
  • The Ukrainian government has said the facilities are legitimate military targets because the company supplies Russia’s frontline troops.
    Lauren Kent, CNN Money, 9 Aug. 2026
  • He was taken to the medical tent for an immediate examination, then led back inside the practice facility for further evaluation.
    Nicki Jhabvala, New York Times, 9 Aug. 2026
Noun
  • Sustainability initiatives With the ship redo, Windstar added more energy efficient engines that reduce emissions of nitrous and sulfur oxides Advanced wastewater treatment systems were also installed.
    Condé Nast, Condé Nast Traveler, 12 Aug. 2026
  • Manske had campaigned as a political outsider, urging reforms to the state’s healthcare and election systems, while also calling for a ban on data centers.
    Molly Parks, The Washington Examiner, 12 Aug. 2026
Verb
  • The softening job market may complicate the calculation for the Federal Reserve, which is also battling stubborn inflation.
    Scott Horsley, NPR, 7 Aug. 2026
  • The report complicates the outlook for the Federal Reserve, where policymakers are divided over the path for interest rates.
    Yun Li,Sean Conlon,Hugh Leask, CNBC, 7 Aug. 2026
Adjective
  • The company is also profitable, a financial positioning that gives the founder the freedom to invest in higher quality materials, moving Sézane slightly upmarket, while shifting the editorial styling to feel more sophisticated.
    Hilary Milnes, Vogue, 10 Aug. 2026
  • But for most Americans, direct access has remained limited by high investment minimums, limited access to private transactions and a market that has historically favored large, sophisticated investors.
    Artem Milinchuk, Forbes.com, 10 Aug. 2026
Adjective
  • On the other hand, detailed reviews of individual high-cost claims frequently reveal inefficient areas in an employer’s health plan.
    Bruce Roffe, Forbes.com, 12 Aug. 2026
  • There’s a 7-inch smart TFT display supporting turn-by-turn navigation and detailed trip graphs that map speed, elevation, and battery state of charge against route data.
    New Atlas, New Atlas, 12 Aug. 2026
Noun
  • Heavy deposits could collapse roofs, contaminate water, damage machinery, bury crops, disrupt power networks, and make roads difficult to use.
    Atharva Gosavi, Interesting Engineering, 12 Aug. 2026
  • During a 2024 ground-breaking ceremony for the bridge, city and state leaders called it a key link connecting JOST trails with the coastal trail network, the Santa Ana Mountains, and the Cleveland National Forest.
    Julie Sharp, CBS News, 12 Aug. 2026

Browse Nearby Words

Cite this Entry

“Complex.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/complex. Accessed 15 Aug. 2026.

More from Merriam-Webster on complex

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!