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 largest vessels, meanwhile, are being designed with fitness equipment and medical-grade treatment spaces more commonly found in clinics. — Chrissie McClatchie, Robb Report, 19 Sep. 2026

Fitbit Charge Fitness Tracker Deal The Fitbit Charge 6 keeps things focused on actual fitness tracking without trying to become a tiny phone on your wrist. — Juhi Wadia, PC Magazine, 18 Sep. 2026

Beyond the celebrity and sports dimensions of the event, both the gala and the festival will include participation from experts in psychology, fitness, fashion, mindfulness and many other areas. — Dade Hayes, Deadline, 18 Sep. 2026

Along with the shoe, On also announced the signing of athletes Alexander Roncevic and Ida Mathilde Steensgaard in the competitive fitness racing space of Hyrox. — Stephen Garner, Footwear News, 18 Sep. 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