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

There is also a full-service salon and 24-hour fitness center. —Condé Nast, Condé Nast Traveler, 11 June 2026

Gilad Janklowicz, a fitness instructor whose signature syndicated TV program Bodies In Motion brought daily exercise routines to viewers newly dazzled by the exercise and aerobics movement of the 1980s and ’90s, died Tuesday, June 9. —Greg Evans, Deadline, 10 June 2026

Hotels and resorts are converting traditional spas into health and longevity destinations, offering fitness assessments, sleep tracking and structured longevity programs that promise to reduce stress and support healthier aging. —Hanna Wickes, Sacbee.com, 10 June 2026

Top Long-Distance Walking Shoes to Buy Online Walking might be the most widespread form of exercise, but, like with any fitness activity, your gear matters. —Oscar Hartzog, Footwear News, 10 June 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