- any of numerous small, wingless bloodsucking insects of the order Siphonaptera, parasitic upon mammals and birds and noted for their ability to leap.
- either of two common fleas of the genus Ctenocephalides, the very small, black C. felis (cat flea) or the similar but larger C. canis (dog flea), both of which infest cats, dogs, and occasionally humans.
- any of various small beetles and crustaceans that leap like a flea or swim in a jumpy manner, as the water flea and beach flea.
- flea in one’s ear,
- a disconcerting rebuke or rebuff: The next time he shows his face around here he’ll get a flea in his ear.
- a broad hint.
- any small wingless parasitic blood-sucking insect of the order Siphonaptera, living on the skin of mammals and birds and noted for its power of leaping
- any of various invertebrates that resemble fleas, such as the water flea and flea beetle
- flea in one’s ear informal a sharp rebuke
Old English flea, from Proto-Germanic *flauhaz (cf. Old Norse flo, Middle Dutch vlo, German Floh), perhaps related to Old English fleon “to flee,” with a notion of “the jumping parasite,” or perhaps from PIE *plou- “flea” (cf. Latin pulex, Greek psylla; see puce).
Flea-bag “bed” is from 1839; flea circus is from 1886; flea collar is from 1953.
“A man named ‘Mueller’ put on the first trained-flea circus in America at the old Stone and Austin museum in Boston nearly forty years ago. Another German named ‘Auvershleg’ had the first traveling flea circus in this country thirty years ago. In addition to fairs and museums, I get as high as $25 for a private exhibition.” [“Professor” William Heckler, quoted in “Popular Mechanics,” February 1928. Printed at the top of his programs were “Every action is visible to the naked eye” and “No danger of desertion.”]
- Any of various small, wingless, bloodsucking insects of the order Siphonaptera that have legs adapted for jumping and are parasitic in the hair and feathers of warm-blooded animals.
In addition to the idioms beginning with flea
- flea in one’s ear, a
- flea market
- hurt a fly (flea)