Find Synonyms

fastness Synonyms

Another word for fastness

Choosing another word for fastness depends on context, so the 17 synonyms and similar words below are separated across 3 exact definitions and ranked by match strength.
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• noun (Context 1)

The quality or state of being firmly fixed, secure, or resistant to fading or washing (especially of a dye or color).

Usage Example

"The textile laboratory tested the fabric for color permanence under prolonged ultraviolet light."

Strong
permanence
stability
firmness
durability
fixity

• noun (Context 2)

The quality or state of moving or happening at high speed; rapidity.

Usage Example

"The sheer speed of the modern telecommunications network allows instantaneous global data transfer."

Strongest
speed
swiftness
rapidity
quickness
Strong
celerity
fleetness

• noun (Context 3)

A secure, remote, or fortified place, such as a mountain stronghold or refuge that is difficult to access.

Usage Example

"The endangered snow leopards retreated into the rocky fastnesses of the high Himalayas."

Strongest
stronghold
fortress
Strong
citadel
bastion
sanctuary
refuge

Opposites of fastness

The opposite of fastness shifts depending on context. Common opposites include:

slowness
sluggishness
instability
impermanence
looseness
tardiness
See all opposites of fastness

• Nearby Words

fastidious
fastidiously
fastish
fastness
fastpitch
fastwalk
fat

Cite this Entry

Wordmom. (2026). Synonyms for Fastness. In Wordmom Thesaurus. Retrieved Nov 5, 2026, from https://wordmom.com/synonyms/fastness
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