Vicious vs Diabolical - What's the difference?

As adjectives the difference between vicious and diabolical

is that vicious is pertaining to vice; characterised by immorality or depravity while diabolical is extremely wicked or cruel.

* (obsolete)

(en-adj)

Pertaining to vice; characterised by immorality or depravity.

*, Folio Society, 2006, vol.1, p.195:

*:We may so seize on vertue, that if we embrace it with an over-greedy and violent desire, it may become vicious .

Evil, immoral or depraved.

Violent, destructive and cruel.

Savage and aggressive.

* vicious circle

(en adjective)

Extremely wicked or cruel.

Of or concerning the devil; satanic.

* diabolically * diabolicalness