hierarchal vs hierarchical

hierarchal and hierarchical both are adjectives.

Word	Noun	Adjective	Verb	Adverb
hierarchal	No	Yes	No	No
hierarchical	No	Yes	No	No

As adjectives, hierarchal and hierarchical are synonyms defined as:

hierarchal and hierarchical: classified according to various criteria into successive levels or layers

Other synonyms of hierarchal include hierarchic.

hierarchal (adjective)	hierarchical (adjective)
classified according to various criteria into successive levels or layers	classified according to various criteria into successive levels or layers