[fa-stid-ee-uh s, fuh-]
  1. excessively particular, critical, or demanding; hard to please: a fastidious eater.
  2. requiring or characterized by excessive care or delicacy; painstaking.

Origin of fastidious

1375–1425; late Middle English < Latin fastīdiōsus squeamish, equivalent to fastīdi(um) lack of appetite, disgust, perhaps by syncope of *fastutīdium (fastu-, combining form of fastus pride, conceit + -tīdium combining form of taedium tedium) + -ōsus -ous
Related formsfas·tid·i·ous·ly, adverbfas·tid·i·ous·ness, nounhy·per·fas·tid·i·ous, adjectivehy·per·fas·tid·i·ous·ly, adverbhy·per·fas·tid·i·ous·ness, nounnon·fas·tid·i·ous, adjectivenon·fas·tid·i·ous·ly, adverbnon·fas·tid·i·ous·ness, nouno·ver·fas·tid·i·ous, adjectiveo·ver·fas·tid·i·ous·ly, adverbo·ver·fas·tid·i·ous·ness, nounul·tra·fas·tid·i·ous, adjectiveul·tra·fas·tid·i·ous·ly, adverbul·tra·fas·tid·i·ous·ness, nounun·fas·tid·i·ous, adjectiveun·fas·tid·i·ous·ly, adverbun·fas·tid·i·ous·ness, noun

Synonym study

1. See particular. Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for non-fastidious


  1. very critical; hard to please
  2. excessively particular about details
  3. exceedingly delicate; easily disgusted
Derived Formsfastidiously, adverbfastidiousness, noun

Word Origin for fastidious

C15: from Latin fastīdiōsus scornful, from fastīdium loathing, from fastus pride + taedium weariness
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for non-fastidious



mid-15c., "full of pride," from Latin fastidiosus "disdainful, squeamish, exacting," from fastidium "loathing, squeamishness," most likely from *fastu-taidiom, a compound of fastus "contempt, arrogance" and taedium "aversion, disgust." Early use in English was both in passive and active senses. Meaning "squeamish, over-nice" emerged in English 1610s. Related: Fastidiously; fastidiousness.

Online Etymology Dictionary, © 2010 Douglas Harper

non-fastidious in Medicine


[fă-stĭdē-əs, fə-]
  1. Possessing or displaying careful, meticulous attention to detail.
  2. Difficult to please; exacting.
  3. Having complex nutritional requirements. Used of microorganisms.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.