of modest morals

A "soft" way of saying dat da referred-to individual is a crooked a**h**e who doesn't give a you-know-what about honestly or integrity, or about how his shamelessly-self-serving actions might harm fellow humans or da environment/economy in general.

Examples of public figures who turned out to be "of modest morals" would be "Tricky Dicky" with Watergate, and Kellyanne Conway with her infamous "alternative facts" claim.