sinful vs iniquitous

sinful and iniquitous both are adjectives.

Word	Noun	Adjective	Verb	Adverb
sinful	No	Yes	No	No
iniquitous	No	Yes	No	No

As adjectives, sinful and iniquitous are synonyms defined as:

sinful and iniquitous: characterized by iniquity; wicked because it is believed to be a sin

Other synonyms of sinful include ungodly.

sinful (adjective)	iniquitous (adjective)
far more than usual or expected	characterized by iniquity; wicked because it is believed to be a sin
having committed unrighteous acts
characterized by iniquity; wicked because it is believed to be a sin