to change into curd; coagulate; congeal.

to spoil; turn sour.

to go wrong; turn bad or fail

Their friendship began to curdle as soon as they became business rivals.

curdle the or one's blood

to fill a person with horror or fear; terrify

a scream that curdled the blood.

noun

acerbate , acidify , acidulate , clabber , clot , coagulate , condense , congeal , curd , ferment , go off , spoil , thicken , turn , turn sour , change , quail , sour

verb

clot , congeal , gelatinize , jell , jelly , set