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 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 According to Wilkins Bratcher, plants that are deficient in magnesium may show signs of yellowing in their lower, older leaves and have a general lack of vitality because magnesium is the central element of the chlorophyll molecule. — Nadia Hassani, The Spruce, 7 Sep. 2026 See All Example Sentences for deficient

Recent Examples of Synonyms for deficient

Adjective

Tools to identify a disrupted maternal and infant gut microbiome are already being developed, but screening without a protocol for what to do next is incomplete medicine.

— Holly Baines, STAT, 14 Oct. 2026
From the Houthis’ perspective, their sovereignty consequently remained incomplete.

— Laurent Bonnefoy, The Conversation, 14 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

Its argument is that insurers have been pricing wildfire risk the wrong way, by looking backward at statistics and sorting homes by zip code.

— Nick Lichtenberg, Fortune, 15 Oct. 2026
The trailer begins as Ziegler’s Mae frantically asks family friend Benny, played by a sleepy Rob Lowe, for help after her big mistake — kissing the wrong brother between Graham Phillips’ Andrew and Elias Kacavas’ Theo.

— Nicole Fell, HollywoodReporter, 15 Oct. 2026

Definition of wrong

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

Measles usually kills two or three people in every 1,000 cases, the WHO says, but the disease can be more deadly in poorer nations because of factors such as malnutrition.

— Arkansas Online, Arkansas Online, 18 Oct. 2026
That receiver sends that poor defender into next week at the pylon.

— Zach Dean OutKick, FOXNews.com, 17 Oct. 2026

Definition of poor

Adjective

Experts attribute that increase partly to issues such as rising healthcare costs, lagging Social Security benefits and insufficient retirement savings.

— Aimee Picchi, CBS News, 14 Oct. 2026
Prosecutors declined to file any charges, citing insufficient evidence.

— Melissa Sanchez, ProPublica, 14 Oct. 2026

Definition of insufficient

Browse Nearby Words

deficiency

deficient

deficiently

See all Nearby Words

Cite this Entry

Style

“Deficient.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/deficient. Accessed 21 Oct. 2026.

Copy Citation

Synonyms of deficient

adjective

Example Sentences

Browse Nearby Words

Cite this Entry

More from Merriam-Webster

Word of the Day

jilt

Popular in Grammar & Usage

Merriam-Webster’s Great Big List of Words You Love to Hate

'Can' vs. 'May'

'Affect' vs. 'Effect'

More Commonly Mispronounced Words

Is it 'nerve-racking' or 'nerve-wracking'?

Popular in Wordplay

The Longest Long Words List

9 Words That Sound Like Insults But Aren't

Did 'orange' the fruit or the color come first?

Even More Bird Names that Sound Like Insults (and Sometimes Are)

12 Lovely and Unusual Words for the Natural World

Popular

Merriam-Webster’s Great Big List of Words You Love to Hate

The Longest Long Words List

9 Words That Sound Like Insults But Aren't

Games & Quizzes