As adjectives the difference between lascivious and lascious
is that lascivious
is wanton; lewd, driven by lust, lustful while lascious
is (obsolete) loose; lascivious.
Wanton; lewd, driven by lust, lustful.
*:The colonel and his sponsor made a queer contrast: Greystone [the sponsor] long and stringy, with a face that seemed as if a cold wind was eternally playing on it. […] But there was not a more lascivious reprobate and gourmand in all London than this same Greystone.
* wanton, lewd, lustful