hierarchical vs hierarchal

hierarchical and hierarchal both are adjectives.

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

As adjectives, hierarchical and hierarchal are synonyms defined as:

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

Other synonyms of hierarchical include hierarchic.

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