Noun

(en noun)

The bubonic plague, the pestilent disease caused by the virulent bacterium ''Yersinia pestis .

(pathology) An epidemic or pandemic caused by any pestilence, but specifically by the above disease.

A widespread affliction, calamity or destructive influx, especially when seen as divine retribution.

Ten Biblical plagues over Egypt, ranging from locusts to the death of the crown prince, finally forced Pharaoh to let Moses's people go.

A grave nuisance, whatever greatly irritates

Bart is an utter plague ; his pranks never cease.

Noun

(en noun)

(pejorative) A person who lives on other people's efforts or expense and gives little or nothing back.

(biology) an organism that lives on or in another organism, 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.

* {{quote-magazine, date=2013-03

, author= , title=The Smallest Cell , volume=101, issue=2, page=83 , magazine= citation , passage=It is likely that the long evolutionary trajectory of Mycoplasma went from a reductive autotroph to oxidative heterotroph to a cell-wall–defective degenerate parasite . This evolutionary trajectory assumes the simplicity to complexity route of biogenesis, a point of view that is not universally accepted.}}

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

(literary, poetic) A climbing plant which is supported by a wall, trellis etc.

* 1813 , (Percy Bysshe Shelley), Queen Mab , I:

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