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

Start with at least three workout days per week to meet your fitness goals. — Angela Ryan Lee, Verywell Health, 6 Aug. 2026

Peloton Interactive — The connected fitness company sank 16% after its fourth quarter results. — Michelle Fox, CNBC, 6 Aug. 2026

There’s Wi-Fi, Bluetooth, NFC and ANT+, a standard often used to broadcast heart rate data in older fitness gadgets. — Andrew Williams, Forbes.com, 6 Aug. 2026

Shared amenities include a fitness center, yoga studio, theater room, wine cellar, offices, and staff quarters on every level. — Demetrius Simms, Robb Report, 5 Aug. 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