bad blood

Noun

bad blood (uncountable)

1. (idiomatic) Feelings of hostility or ill will.
   • The government at home, and the people of the colonies, are getting to have bad blood between them.1843, [James Fenimore Cooper], chapter III, in Wyandotté, or The Hutted Knoll. […], volume (please specify |volume=I or II), Philadelphia, Pa.: Lea and Blanchard, →OCLC
   • [T]here was bad blood between us from a couple of weeks back, and we was only friends in the way of business.1896, Mark Twain [pseudonym; Samuel Langhorne Clemens], chapter 3, in Tom Sawyer, Detective

   Synonyms:

   animosity, animus

2. (idiomatic) A serious feud or long-standing grudge.
   • Now for these and other things (whereof I could tell a thousand) was the reckoning come that night; and not a line we missed of it; soon as our bad blood was up. I like not to tell of slaughter, though it might be of wolves and tigers; and that was a night of fire and slaughter, and of very...1869, R[ichard] D[oddridge] Blackmore, chapter LXXI, in Lorna Doone: A Romance of Exmoor. […], volume (please specify |volume=I to III), London: Sampson Low, Son, & Marston, […], →OCLC

   Synonyms:

   blood feud, vendetta

3. (dated, idiomatic) An inherited immoral or disturbed nature.
   • [I]f we dare not search ourselves close enough to discover the low breeding, the bad blood in us, it will one day come out plain as the smitten brand of the forcat.1882, George MacDonald, chapter 4, in Weighed and Wanting
   • "Humph! Thought there was bad blood somewhere!" he exclaimed […].
     "No!" was the determined answer […]. Because his father was dishonest is no proof that he is a thief."1902, Annie Fellows Johnston, chapter 5, in Flip's ‘Islands of Providence’
4. (regional) A particular disease; in some places, syphilis.