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

Facilities, coaches, physios, fitness coach, nutritionist, psychologist. —James Horncastle, New York Times, 7 May 2026

As the incumbent mayor, Bass had to weather blows from her challengers while trying to sell voters on her fitness for another term, despite a disastrous 2025. —Gustavo Arellano, Los Angeles Times, 7 May 2026

Some fitness experts recommend more rest days for specific muscle groups, while others suggest spacing them farther apart. —Sherri Gordon, Health, 6 May 2026

But before City Council members voted 13-3 to approve the appointment, some questioned Young’s fitness for the role. —Jake Sheridan, Chicago Tribune, 6 May 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