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 of fitness

• 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

Accessibility All of the dining venues and wellness facilities (including the yoga and fitness pavilions and spa treatment rooms) are accessible from within the first floor of the Estate House and the surrounding grounds; the Estate House, along with the Casitas, offer ADA rooms. —Condé Nast, Condé Nast Traveler, 21 Feb. 2026

This is especially relevant for physically active individuals, older adults, and those recovering from illness or injury—protein needs vary based on many variables, including age, activity level, body composition, health status, and fitness goals. —Riley Wofford, Martha Stewart, 21 Feb. 2026

Emil Iverson, who's also from Trondheim, spent much of the past year shadowing Klæbo in an attempt to boost his own fitness and skills — even traveling to a training camp in Utah with him. —Nathaniel Herz, NPR, 21 Feb. 2026

Tennis, pickleball, and basketball courts; a soccer pitch; bocce ball; and a fitness center help everyone in the family stay active. —Beth Luberecki, USA Today, 21 Feb. 2026

Word History

First Known Use

1574, 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