acephalism vs acephaly

acephalism and acephaly both are nouns.

Word	Noun	Adjective	Verb	Adverb
acephalism	Yes	No	No	No
acephaly	Yes	No	No	No

As nouns, acephalism and acephaly are synonyms defined as:

acephalism and acephaly: absence of the head (as in the development of some monsters)

Other synonyms of acephalism include acephalia.

acephalism (noun)	acephaly (noun)
absence of the head (as in the development of some monsters)	absence of the head (as in the development of some monsters)