acephaly

English Thesaurus

1. absence of the head (as in the development of some monsters) (noun.state)

hypernym	:	abnormalcy, abnormality,
definition	:	an abnormal physical condition resulting from defective genes or developmental deficiencies (noun.state)

part meronym	:	monster, teras,
definition	:	(medicine) a grossly malformed and usually nonviable fetus (noun.animal)