jellyfish

noun

jel·​ly·​fish ˈje-lē-ˌfish 

1

a

: the typically free-swimming, bell-shaped, usually sexually-reproducing solitary or colonial form of a cnidarian in which the whorls of tentacles lined with nematocysts arise and hang down from the margin of the nearly transparent, gelatinous bell : medusa

especially : a large medusa characteristic of the siphonophores and scyphozoans (such as the sea nettle or box jellyfish)

b

: siphonophore

c

: ctenophore

2

: a person lacking backbone or firmness

Illustration of jellyfish

• jellyfish 1a

Synonyms

• doormat
• namby-pamby
• pushover
• reed
• weakling
• wimp

Examples of jellyfish in a Sentence

a jellyfish who was afraid to tell her boss that her latest brainstorm was just plain bad

Recent Examples on the Web

Monger battled jellyfish stings, exhausting winds and energy-sapping heat to finish the course which winds itself around Hawaii’s Big Island. —Amanda Davies, CNN, 21 Mar. 2025

Examples include the jellyfish cut, where there is a solid ‘bob’ with longer strands at the bottom. —Laia Farran Graves, Forbes, 19 Mar. 2025

Getty Images One element of the original jellyfish cut that remains: baby bangs. —Marci Robin, Allure, 6 Mar. 2025

Designed by Karl Lagerfeld for the opulent 1992 fall couture show, Kardashian’s black gown features a Medusa-style corset with a structured bodice and delicate spaghetti straps, falling into a pleated black silk skirt and chiffon jellyfish underskirt. —Margaux Anbouba, Vogue, 2 Mar. 2025

Word History

First Known Use

1818, in the meaning defined at sense 1a

Phrases Containing jellyfish

• box jellyfish

Rhymes for jellyfish

• cuttlefish
• sablefish
• bluefish
• catfish
• codfish
• crawfish
• dogfish
• finfish
• flatfish
• goldfish
• groundfish
• kingfish

Kids Definition

jellyfish

noun

jel·​ly·​fish ˈjel-ē-ˌfish 

1

: any of numerous free-swimming coelenterate animals that reproduce sexually and have a jellylike, saucer-shaped, and usually nearly transparent body and tentacles with stinging cells

2

: any of various sea animals that resemble a jellyfish

Medical Definition

jellyfish

noun

jel·​ly·​fish ˈjel-ē-ˌfish 

: a free-swimming marine coelenterate that is the sexually reproducing form of a hydrozoan or scyphozoan and has a nearly transparent saucer-shaped body and extensible marginal tentacles studded with stinging cells