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

• 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

Experts recommend pairing Zone 2 workouts with strength or high-intensity training for the best overall fitness results. —Brian Mastroianni, Health, 23 Oct. 2025

With her newfound fame, Nicole has helped to empower dozens of women in the wellness space and has collaborated with fitness brands like Alo, Fabletics, and Champs. —Jason Pham, StyleCaster, 23 Oct. 2025

However, part-time military members lack access to fitness resources even though they're held to the same standards as their active duty peers. —Davis Winkie, USA Today, 23 Oct. 2025

The 65-year-old exercise instructor and fitness personality didn’t rely on gimmicks to get Mel Owen’s attention. —Jessica Radloff, Glamour, 23 Oct. 2025

Word History

First Known Use

1580, 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