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

Trump has frequently critiqued the cognitive fitness of his predecessor, Biden. —David Bauder, Fortune, 11 Dec. 2025

Alongside your regular fitness routine, Zinn recommends incorporating both a mobility practice and a fascia practice. —Jennifer Shanker, Flow Space, 11 Dec. 2025

Lowe found his entrepreneurial spirit to help lead a health and fitness product after a chance meeting with a famous pro wrestler. —James Varsallone, Miami Herald, 11 Dec. 2025

Every year from December to January, home fitness equipment flies off the shelves and gyms overflow with people motivated to make a strong start on their physical health goals for the new year. —Barbara White, Kansas City Star, 10 Dec. 2025

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