fitness

noun

fit·​ness ˈfit-nəs 

1

: the quality or state of being fit

2

: the capacity of an organism to survive and transmit its genotype to reproductive offspring as compared to competing organisms

also : the contribution of an allele or genotype to the gene pool of subsequent generations as compared to that of other alleles or genotypes

Synonyms

• health
• wellness
• strength

Examples of fitness in a Sentence

a gymnastics program promoting fitness and agility in school-aged children

I have to question the fitness of wearing a bright red dress to a funeral.

Recent Examples on the Web

Factors such as fitness level, underlying health conditions, and age can significantly affect a person's ability to meet a high step count. —Chelsea Rae Bourgeois, Health, 2 Oct. 2025

Researchers said this is an example of commensalism, an association between two species in which one benefits from the association without impacting the fitness of the other. —Lauren Liebhaber, Miami Herald, 2 Oct. 2025

Most complete the challenge anywhere between 10 to 16 hours, depending on fitness and conditions. —Tiffany Acosta, AZCentral.com, 1 Oct. 2025

The connected fitness company on Wednesday unveiled a slate of products and training offerings to advance its mission of supporting the total well-being of its 6 million members. —Jean E. Palmieri, Footwear News, 1 Oct. 2025

Word History

First Known Use

1580, in the meaning defined at sense 1

Phrases Containing fitness

• physical fitness

Rhymes for fitness

• witness
• eyewitness
• unfitness

Medical Definition

fitness

noun

fit·​ness ˈfit-nəs 

: the capacity of an organism to survive and transmit its genotype to reproductively fertile offspring as compared to competing organisms

also : the contribution of an allele or genotype to the gene pool of subsequent generations as compared to that of other alleles or genotypes