fastness

noun

fast·​ness ˈfas(t)-nəs 

1

: the quality or state of being fast: such as

a

: the quality or state of being fixed

b

: the quality or state of being swift

c

: colorfast quality

d

: resistance (as of an organism) to the action of a usually toxic substance

2

a

: a fortified or secure place

b

: a remote and secluded place

vacationed in their mountain fastness

Synonyms

• celerity
• fleetness
• haste
• hurry
• quickness
• rapidity
• rapidness
• speed
• speediness
• swiftness
• velocity

Examples of fastness in a Sentence

the amazing fastness with which the boy took his shower had us wondering if he'd used any water

the guerillas retreated to their network of hidden fastnesses deep within the mountains

Recent Examples on the Web

Tat-Fung’s Downtown collection of blue, black and gray fabrics outperform conventional denim in color fastness, according to Tim Huesemann, the mill’s sales director. —Angela Velasquez, Sourcing Journal, 22 Oct. 2024

This advancement enables dyeing with Basic dyes, promising enhanced dye uptake and superior wash fastness compared to traditional Reactive dyes. —Sj Studio, Sourcing Journal, 13 Sep. 2024

The Neutral Ground had cowboys (or Cow Boys), Indians, cavalry attacks and rescues, and secret woodland fastnesses known only to the canniest frontiersman. —Ian Frazier, The New Yorker, 15 July 2024

The technology uses specific formaldehyde-free agents to enhance the dyeing process of raw garments, resulting in a bright and deep indigo color, improving wash and rubbing fastness, and increasing lightfastness and levelness. —Andrea Onate, WWD, 12 June 2024

Fearing extermination, members of the Yezidi sect fled to their ancestral fastness on Mount Sinjar. —Timothy William Waters, Foreign Affairs, 29 Mar. 2016

Branagh returns as Hercule Poirot, who has retired to a Venetian fastness. —Anthony Lane, The New Yorker, 15 Sep. 2023

When using natural dyes, there tend to be issues with color fastness and shade consistency. —Esha Chhabra, Forbes, 22 Feb. 2023

Unlike the Brahui the Burusho are very isolated in the mountainous fastness of Baltistan in northern Pakistan. —Razib Khan, Discover Magazine, 20 Dec. 2010

Word History

First Known Use

before the 12th century, in the meaning defined at sense 1

Kids Definition

fastness

noun

fast·​ness ˈfas(t)-nəs 

1

: the quality or state of being fast

2

: a fortified or secure place

Medical Definition

fastness

noun

fast·​ness ˈfas(t)-nəs 

: resistance (as of an organism) to the action of a usually toxic substance

streptomycin fastness developed by a strain of tubercule bacillus