sinful vs ungodly

sinful and ungodly both are adjectives.

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

As adjectives, sinful and ungodly are synonyms defined as:

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

Other synonyms of sinful include iniquitous.

sinful (adjective)	ungodly (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