blood clotting vs curdling

blood clotting and curdling both are nouns.

Word	Noun	Adjective	Verb	Adverb
blood clotting	Yes	No	No	No
curdling	Yes	No	No	No

As nouns, curdling is a hypernym of blood clotting; that is, curdling is a word with a broader meaning than blood clotting:

blood clotting: a process in which liquid blood is changed into a semisolid mass (a blood clot)
curdling: the process of forming semisolid lumps in a liquid

Other hypernyms of blood clotting include clotting, coagulation.

blood clotting (noun)	curdling (noun)
a process in which liquid blood is changed into a semisolid mass (a blood clot)	the process of forming semisolid lumps in a liquid