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

Amenities include a grab-and-go deli, bar and lounge, and 24-hour fitness center. —Bon Appétit, Bon Appetit Magazine, 4 Dec. 2025

Whether or not these fitness-meets-fashion forays land is another question altogether. —Christina Holevas, Vogue, 4 Dec. 2025

AvalonBay’s new apartment community will feature amenities such as a fitness center, pool, work lounge, clubhouse, rooftop deck and a WAG Pet Spa. —George Avalos, Mercury News, 4 Dec. 2025

Injectable peptides have surged in popularity as a wellness trend promoted by celebrities and fitness influencers. —Stephanie Brown, Verywell Health, 4 Dec. 2025

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