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
Karl Mayer targets faster production of spacer fabrics Karl Mayer is preparing to demonstrate two Jacquard warp-knitting machines designed to produce more complex spacer fabrics for athletic footwear and performance apparel. — Alexandra Harrell, Footwear News, 12 Nov. 2026 About how many complex networks look like and bring it back to the material space. — Quanta Magazine, 12 Nov. 2026
Noun
The suspect was fatally shot by a security guard during an exchange of gunfire inside a cafeteria in the Tampa-area Citibank office complex, according to authorities. — Meredith Deliso, ABC News, 5 Nov. 2026 In June, Sapov showed up at the victim’s apartment complex in Dallas, after traveling from Toronto, Canada, according to court filings. — Maven Navarro, Fort Worth Star-Telegram, 5 Nov. 2026 See All Example Sentences for complex
Recent Examples of Synonyms for complex
Adjective
  • But if the aircraft also loses access to reliable navigation data, the situation can become considerably more complicated.
    — Kaif Shaikh, Interesting Engineering, 8 Nov. 2026
  • But at the same time, domestic attacks involving guns have increased this year, leaving law enforcement, advocates and other criminal justice stakeholders taking stock of a complicated year.
    — Caroline Kubzansky, Chicago Tribune, 8 Nov. 2026
Adjective
  • Indeed, this is perhaps best illustrated by the Alta Moda line of Dolce & Gabbana, which has featured intricate beading, delicate lace, sculptural drapery, complicated basketry, and lush floral appliqués.
    — Alicja Zelazko, Encyclopedia Britannica, 6 Nov. 2026
  • The intricate weave was created using a relatively new powder-bed printing process.
    — Jazz Tangcay, Variety, 6 Nov. 2026
Noun
  • Ukraine's Energy Ministry said Saturday's missile attacks damaged networks that carry electricity from nuclear power plants to Kyiv and central regions, as well as multiple other power facilities.
    — Arkansas Online, Arkansas Online, 8 Nov. 2026
  • Factories can create digital twins of individual machines, production lines, or entire facilities to monitor equipment health, identify bottlenecks, and optimize production schedules.
    — Kaif Shaikh, Interesting Engineering, 8 Nov. 2026
Noun
  • The plant went offline soon after being captured by Russia early in the war, but needs power to keep essential cooling systems running.
    — Arkansas Online, Arkansas Online, 9 Nov. 2026
  • This allows manufacturers to use the machine for productive work while its AI system gathers operational data.
    — Jijo Malayil, Interesting Engineering, 9 Nov. 2026
Verb
  • DeSantis' 2024 campaign was marred by political infighting that drew national attention and was complicated by overspending despite receiving immense donor support.
    — Hannah Demissie, ABC News, 7 Nov. 2026
  • There wasn’t too much time to dwell on that, as the mission was complicated by the news of a prison break.
    — Megan Vick, Variety, 7 Nov. 2026
Adjective
  • The power channels through a sophisticated 9-speed automatic transmission to a single, massive 12-inch (305-mm) wide rear tire.
    — New Atlas, New Atlas, 7 Nov. 2026
  • Glossy, Waist-Length Hair Demi Moore’s waist-grazing, glossy mane proves that super-long hair can still look polished and sophisticated.
    — Colleen Sullivan, InStyle, 7 Nov. 2026
Adjective
  • Related AlphaGenome 2 was trained on more than 100 million individual cell profiles across 68 tissues to give it that more detailed view.
    — Robert Hart, The Verge, 11 Nov. 2026
  • Now, a team of international researchers has developed one of the most detailed models yet of the early universe, according to a recent study published in the scientific journal Monthly Notices of the Royal Astronomical Society.
    — Taylor Nicioli, CNN Money, 11 Nov. 2026
Noun
  • The legal defense army The Left developed a legal advocacy network to support street agitators well before 2020.
    — Hudson Crozier, The Washington Examiner, 9 Nov. 2026
  • In one of the biggest crackdowns on religious activity in recent years, authorities in October 2025 arrested 30 leaders of Zion Church, one of the country’s largest underground church networks, following overnight raids in several cities.
    — ABC News, ABC News, 9 Nov. 2026

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Cite this Entry

“Complex.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/complex. Accessed 14 Nov. 2026.

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