DEFICIENT Synonyms: 257 Similar and Opposite Words

deficient

adjective

di-ˈfi-shənt

Definition of deficient

as in incomplete

lacking some necessary part a diet deficient in calcium can lead to weak bones

Synonyms & Similar Words

Relevance

Antonyms & Near Antonyms

as in unacceptable

falling short of a standard woefully deficient eyesight kept him out of military service

Synonyms & Similar Words

Antonyms & Near Antonyms

as in lacking

not coming up to an expected measure or meeting a particular need too deficient in common sense to be trusted to stay by himself

Synonyms & Similar Words

Antonyms & Near Antonyms

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 deficient Of course, supplementing with vitamin D is especially helpful for those who are deficient. — Nicole Catanese, InStyle, 25 Sep. 2026 High base, cuts to public capex for meeting fiscal deficit targets and the impact of deficient rains on sowing patterns are some of the key reasons the brokerage expects India’s growth to slow over the next few quarters. — Priyanka Salve, CNBC, 14 Sep. 2026 There is nonexistent depth, disastrous allocation of resources and a roster so deficient that the general manager who constructed it has already been dismissed. — Chandler Rome, New York Times, 13 Sep. 2026 The inspector found unclean conditions and deficient handwashing practices and sanitation methods, according to the spokesperson. — Harriet Ramos, Fort Worth Star-Telegram, 9 Sep. 2026 See All Example Sentences for deficient

Recent Examples of Synonyms for deficient

Adjective

And when records are incomplete, modern tools have the ability to impute missing values and attach a confidence score to each estimate, so the person reviewing the output sees both the conclusion and the margin of uncertainty around it.

— Amanda Turcotte, Forbes.com, 20 Oct. 2026
Documentation can be incomplete, and essential business rules may exist only in the original code.

— Aamir Khollam, Interesting Engineering, 19 Oct. 2026

Definition of incomplete

Adjective

Detection is no substitute for prevention, not when consequences are truly unacceptable.

— Andrew Ginter, Forbes.com, 20 Oct. 2026
The win won’t change what’s frankly been an unacceptable campaign for a program that was 18-1-4 just two seasons ago.

— Ryan Kartje, Los Angeles Times, 19 Oct. 2026

Definition of unacceptable

Adjective

Illinois already ranks among the states with the highest property taxes in the nation, yet substantive efforts to relieve this burden remain entirely lacking.

— Chicago Tribune, Chicago Tribune, 14 Oct. 2026
The Detroit Free Press and other Michigan- and national-based media organizations have said the claims are misleading or lacking context.

— Barnini Chakraborty, The Washington Examiner, 9 Oct. 2026

Definition of lacking

Adjective

Some experts believe this is a good start, but many see it as wholly inadequate.

— Allison Parshall, Scientific American, 20 Oct. 2026
California officials dispute the federal approach, saying the government did not provide the evidence or methodology needed to assess the list and gave the state an inadequate deadline.

— Los Angeles Times, Los Angeles Times, 20 Oct. 2026

Definition of inadequate

Adjective

Disease that has spread to those organs is associated with poorer treatment outcomes.

— Annika Kim Constantino, CNBC, 24 Oct. 2026
They were frustrated with teacher shortages and poor conditions at schools, including overcrowded classrooms and dilapidated buildings.

— James Cirrone , Brittany Miller, FOXNews.com, 24 Oct. 2026

Definition of poor

Adjective

The report also noted that insufficient demand for recycled textiles presents an additional challenge, since recyclers aren’t likely to scale their efforts without a market for the recycled product.

— Jennifer Bringle, Footwear News, 22 Oct. 2026
For her family, protections put in place before the violence proved insufficient.

— Ariella Noveck, FOXNews.com, 22 Oct. 2026

Definition of insufficient

Adjective

Poetry gets left behind by the exigency of character development or, in the movie’s self-defeating logic, because the art form doesn’t really matter and is only a lame excuse for people who won’t take responsibility and grow up.

— Literary Hub, Literary Hub, 16 Oct. 2026
Blumenthal hopes to see action on KOSA in the lame-duck session.

— Lisa Hagen, Hartford Courant, 2 Oct. 2026

Definition of lame

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deficiency

deficient

deficiently

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“Deficient.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/deficient. Accessed 28 Oct. 2026.

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Synonyms of deficient

adjective

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