From , from , from , from noun use of adjective meaning "feeding beside", from παρά ("beside") + σῖτος ("food").

• (RP) IPA: /ˈpæɹəˌsaɪt/
• (America) IPA: /ˈpæɹəˌsaɪt/, /ˈpɛɹəˌsaɪt/

parasite (plural parasites)

1. (biology) An organism that lives on or in another organism of a different species, deriving benefit from living on or in that other organism, while not contributing towards that other organism sufficiently to cover the cost to that other organism.

   Lice, fleas, ticks and mites are widely spread parasites.

   • 1834, L[etitia] E[lizabeth] L[andon], chapter XIX, in Francesca Carrara. […], volume III, London: Richard Bentley, […], (successor to Henry Colburn), →OCLC ↗, page 154 ↗:

     ...and the mistletoe crept round many of the oaks—that pleasant parasite, whose associations belong rather to the hearth and lighted hall than to its native branches.

   1. (informal, specifically) An internal parasite that is an animal or protist.
2. (pejorative) A person who lives on other people's efforts or expense and gives little or nothing back. [from 16th c.]

   Synonyms: Thesaurus:scrounger

3. (pejorative) A sycophant or hanger-on.
4. (literary, poetic) A climbing plant which is supported by a wall, trellis etc. [from 19th c.]
   • 1813, Percy Bysshe Shelley, “Canto I”, in Queen Mab; […], London: […] P. B. Shelley, […], →OCLC ↗, page 3 ↗:

     Her golden tresses shade / The bosom's stainless pride, / Curling like tendrils of the parasite / Around a marble column.

5. (historical) A retainer or companion of an ancient Celtic warrior, who praised him in song or poetry at gatherings; a bard.
6. (aviation) A component of a composite aircraft which is carried aloft and air-launched by a larger carrier aircraft or mother ship to support the primary mission of the carrier; a parasite aircraft.
7. (retail, used attributively) An isolated (FSDU) (freestanding display unit )

• commensal (doing no noticeable harm)
• mutualism or sometimes symbiote (beneficial)

• French: parasite, profiteur
• German: Parasit
• Italian: parassita
• Portuguese: parasita
• Russian: парази́т
• Spanish: parásito

• French: parasite
• German: Schmarotzer, Parasit
• Italian: parassita
• Portuguese: parasita, verme
• Russian: парази́т
• Spanish: parásito

parasite (parasites, present participle parasiting; simple past and past participle parasited)

1. (rare) To parasitize.