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

While fitness tracking companies typically claim consumer data is safe, some tracking apps have already leaked data to Big Tech companies. — Sparkle Rainey Tribune News Service, Arkansas Online, 3 Oct. 2026

Over the past couple of centuries interest in male muscle development and fitness has peaked during times of economic precarity and conflict. — Gavin Francis, The New York Review of Books, 3 Oct. 2026

All officers must meet fitness for duty requirements to be capable of performing their vital national security function while simultaneously creating a welcoming and professional environment for travelers. — Sasha Rogelberg, Fortune, 1 Oct. 2026

Those amenities include a pool, fitness center and pickleball courts. — Desiree Mathurin, Charlotte Observer, 1 Oct. 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