Pronunciation: (kûr'dl),[key] —v.t., v.i.,-dled, -dling. 1. to change into curd; coagulate; congeal.
2. to spoil; turn sour.
3. to go wrong; turn bad or fail: Their friendship began to curdle as soon as they became business rivals. 4. curdle the or one's blood, to fill a person with horror or fear; terrify: a scream that curdled the blood.