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

The property also houses its own private theater, wine cellar, tasting room, game room, poker room and fitness center. — Colson Thayer, PEOPLE, 2 July 2026

On the other were work uniforms engineered for humanoids on industrial sites, spanning hazardous operations, smart farming, fitness coaching and auto maintenance. — Sj Studio, Footwear News, 2 July 2026

The Agatha Christie penthouse, for example, comes with a fitness room, a marble bath, and a spacious terrace with a jacuzzi. — Rachel Cormack, Robb Report, 2 July 2026

Next to the pitch were tents artificially heated to a minimum of 95 degrees Fahrenheit, where players completed fitness tests on exercise bikes while staff measured their performance. — Nancy Walecki, The Atlantic, 2 July 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