fastidious

adjective

fas·​tid·​i·​ous fa-ˈsti-dē-əs 

fə-

1

a

of a person's work, approach, etc. : extremely or excessively careful or detailed

fastidious research

scenes drawn in fastidious detail

… he took fastidious care of his cars.

—Marga Lincoln

… his fastidious approach to tasks—making detailed, several-page lists on yellow pads …

—Josh Dawsey et al.

… her fastidious—but never fussy—prose …

—Kirkus Reviews

But many food poisoning outbreaks are complicated. Some are never solved. Cracking them is fastidious work.

—Lynne Terry

Just as famous was the 1965 Jaguar [guitar] he played, which Fender has recreated with fastidious attention to detail.

—spin.com

b

of a person or trait : characterized by a meticulous, sensitive, or demanding attitude

a fastidious dresser/eater

… a collector with fastidious taste.

—Martin Chulov

True to her fastidious nature, Peretti hand-selected all of the stones included in the collections …

—Misty White Sidell

: such as

(1)

: having high and often capricious standards

… critics … so fastidious that they can talk only to a small circle of initiates.

—Granville Hicks

(2)

: characterized by extreme or excessive concern about cleanliness or neatness

a fastidious housekeeper

But in the hazy panic of the time, many people had already taken up fastidious habits: quarantining packages at the door, bleaching boxes of cereal brought back from the store, wearing hospital booties outdoors.

—Gregory Barber

Disorder and dirt filled the rough cabin, or so it seemed to her fastidious eye.

—William MacLeod Raine

2

: having complex nutritional requirements

fastidious microorganisms

3

archaic : scornful

fastidiously adverb

fastidiousness noun

Did you know?

Fastidious Has a Disgusting Past

If you presume that the adjective fastidious bears some relation to fast, not so fast. Fastidious comes from Latin fastidium, meaning "aversion" or "disgust." Fastidium is believed to be a combination of fastus, meaning "arrogance," and taedium, "irksomeness" or "disgust." (Taedium is also the source of tedium and tedious.) In keeping with its Latin roots, fastidious once meant "haughty," "disgusting," and "disagreeable," but the word is now most often applied to people who are very meticulous or overly difficult to please, or to work which reflects a demanding or precise attitude. Our own fastidiousness requires us to point out that the familiar adjective fast comes not from Latin, but from Old English.

Synonyms

• careful
• nice
• particular
• finicky
• exacting
• meticulous
• persnickety
• picky
• fussy
• finical
• dainty
• pernickety [chiefly British]
• demanding
• choosy
• delicate
• selective
• choosey

Examples of fastidious in a Sentence

My mother had always been the most fastidious and organized of people—a wet ring left on her coffee table by a glass could drive her to distraction. —John B. Judis, New Republic, 14 Oct. 1996

"I'll stop off and get us a sandwich," said Matthew.  … Tony, a fastidious eater, sighed. —Penelope Lively, City of the Mind, 1991

Though he prides himself on being hip, he is too fastidious to do anything dangerous or dirty. —Jay McInerney, Bright Lights, Big City, 1984

He is fastidious about keeping the house clean.

She was too fastidious to do anything that might get her dirty.

Recent Examples on the Web

As the mission sprints its final lap before launch day, their fastidious preparation stands out as an achievement in its own right. —Matt Alderton, USA Today, 24 Oct. 2025

The convenience factor would start to dwindle, however, if drivers had to stop and wait while the drone located their vehicle, then came in to execute a fastidious landing. —New Atlas, 5 Oct. 2025

Scorn is a salve for her—an enjoyable expression of her fastidious nature and a coping strategy. —Literary Hub, 15 Sep. 2025

The company is nonetheless fastidious about the fundamental details. —Lauren Collins, New Yorker, 15 Sep. 2025

Word History

Etymology

Middle English, from Latin fastidiosus, from fastidium disgust, probably from fastus arrogance (probably akin to Latin fastigium top) + taedium irksomeness — more at tedium

First Known Use

15th century, in the meaning defined at sense 3

Phrases Containing fastidious

• hyper-fastidious

Rhymes for fastidious

• insidious
• invidious
• hideous

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Kids Definition

fastidious

adjective

fas·​tid·​i·​ous fa-ˈstid-ē-əs 

: hard to please : very particular

fastidiously adverb

fastidiousness noun

Medical Definition

fastidious

adjective

fas·​tid·​i·​ous fa-ˈstid-ē-əs, fə- 

: having complex nutritional requirements

fastidious microorganisms

—used of bacteria that grow only in specially fortified artificial culture media