jellyfish
jel.ly.fish \'jel-e--.fish\ n 1a: a free-swimming marine coelenterate that is the sexually reproducing fo rm of a hydrozoan or scyphozoan and has a nearly transparent saucer-shaped body and extensile marginal tentacles studded with stinging cells 1b: SIPHONOPHORE 1c: CTENOPHORE 2: a person lacking backbone or firmness