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 restorative bathhouse offers many treatments, a fitness center and there is a seasonal outdoor pool and lawn club. — Pamela McLoughlin, Hartford Courant, 14 Aug. 2026

Hidemasa Morita, the 31-year-old Japan midfielder signed from Lisbon’s Sporting CP, is struggling to build fitness in pre-season but is expected to be a prominent figure in a holding role. — Chris Weatherspoon, New York Times, 14 Aug. 2026

Wondermind, which was co-founded by Gomez; her mother, Mandy Teefey; and Daniella Pierson in November 2021, touts mental fitness practices and tools. — Marlene Lenthang, NBC news, 14 Aug. 2026

Because of these limitations, physicians usually consider waist circumference, body composition, fitness, blood pressure, blood sugar and cholesterol levels alongside BMI. — Daryl Austin, USA Today, 13 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