Definition of fastness
1 : the quality or state of being fast: such asa : the quality or state of being fixedb : the quality or state of being swiftc : colorfast qualityd : resistance (as of an organism) to the action of a usually toxic substance
2a : a fortified or secure placeb : a remote and secluded place vacationed in their mountain fastness
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 of fastness from the Web
India kept the mostly Hindu rest of Jammu, the Vale itself and the desert-like fastness of Ladakh.
These example sentences are selected automatically from various online news sources to reflect current usage of the word 'fastness.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.
First Known Use of fastness
before 12th century
FASTNESS Defined for English Language Learners
Definition of fastness for English Language Learners
: a place that is difficult to get to or that can be easily defended if it is attacked
Medical Definition of fastness
: resistance (as of an organism) to the action of a usually toxic substance streptomycin fastness developed by a strain of tubercule bacillus
Seen and Heard
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