flea

American  

[flee] / fli /

noun

1. any of numerous small, wingless bloodsucking insects of the order Siphonaptera, parasitic upon mammals and birds and noted for their ability to leap.

2. 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.

3. 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.

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idioms

1. flea in one's ear,

   1. a disconcerting rebuke or rebuff.

      The next time he shows his face around here he'll get a flea in his ear.

   2. a broad hint.

flea British  

/ fliː /

noun

1. 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

2. any of various invertebrates that resemble fleas, such as the water flea and flea beetle

3. informal a sharp rebuke

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flea More Idioms  

More idioms and phrases containing flea

• hurt a fly (flea)

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Etymology

Origin of flea

before 900; Middle English fle, Old English flēah, flēa; cognate with German Floh; akin to flee

Explanation

A flea is a tiny biting insect that's especially common on dogs. If you find one flea in your dog's fur, there may be hundreds more hiding in there. Fleas live by sucking blood from a host — they're parasites. You can just barely see a flea with the naked eye, and when you do spot one it may be hopping, since they're known to jump, sometimes from one animal to another. Flea bites are itchy, and fleas can be tricky to get rid of once they've laid eggs on your dog (or in your bed). Some experts think the word's root s the Old English fleon, "to flee."

Example Sentences

“They called them flea pits because you caught diseases there.”

From Los Angeles Times • Apr. 8, 2026

“I would always use thrifted finds and flea market things in my makeovers, and people would always ask me, ‘Can you sell what you’re using?’” he said.

From Los Angeles Times • Apr. 3, 2026

Toxic chemicals used in pet flea treatments are widespread in rivers across Wales and are harming wildlife, scientists say.

From BBC • Mar. 10, 2026

"A lot of communities are organising flea markets," Lin, a 37-year-old shopper, told AFP.

From Barron's • Mar. 4, 2026

We’d found this movie, Breakin’ at a flea market a few years ago, and we’d watched it at least twenty times already.

From "A Very Large Expanse of Sea" by Tahereh Mafi

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