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

In addition to her fitness pursuits, Bitner flaunted her pastry-making skills and regularly shared photos of her decorative cakes. —Zoey Lyttle, People.com, 15 July 2025

The best rebounder trampolines have become a favorite among fitness pros and physical therapists for low-impact cardio that’s surprisingly effective. —Jordan Galloway, SELF, 15 July 2025

The facility offers high-end amenities, including boutique-style classes, indoor and outdoor fitness zones, and full-size courts. —Sacbee.com, 14 July 2025

There were 90 prospects at the combine who went through 14 fitness tests, measuring aerobics, agility and more. —Jeremy Rutherford, New York Times, 12 July 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