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 main room has a fireplace, tables and chairs, and lots of floor space for yoga, Pilates or other fitness classes. — Emily M. Olson, Hartford Courant, 8 Nov. 2026

Nationwide, more than 1 out of every 4 retail leases signed in the United States this year has been from a cosmetics, beauty service or fitness company, according to CoStar. — Nathaniel Meyersohn, CNN Money, 8 Nov. 2026

In 2022, Jontay had met Johnny Kalaj, a heavily tattooed fitness influencer. — New Yorker, 8 Nov. 2026

Eyes wander up to see the mezzanine balcony, which houses new hotel fitness center, meeting rooms and a member lounge. — Ella Gonzales, Fort Worth Star-Telegram, 8 Nov. 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