LASCIVIOUSNESS (ἀσέλγεια, G816). This term, which is descriptive of wantonness or excess, does not occur frequently in Biblical Gr. In the LXX it is found in two places only (Wisd Sol 14:26; 3 Macc 2:26), in the NT it occurred only eight times. Plato and some Attic authors used the term to denote licentiousness or wanton violence, although the adjectival form generally meant “outrageous.” In Josephus it was used occasionally of lewd women (cf. Jos. War I. xxii. 3). The Eng. word is derived from the Lat., which conveyed the general sense of wantonness, lewdness, or inclination to lust.
International Standard Bible Encyclopedia (1915)
(aselgeia, "licentiousness," "wantonness," "unbridled lust," "shamelessness," "outrageousness"):
Etymologists assign three probable sources of aselgeia, namely:
(1) from a compound of the alpha privitive (negation) and Selge, a Pisidian city whose inhabitants according to Thayer (Lexicon) "excelled in strictness of morals," but, according to Trench, a place whose people "were infamous for their vices";
(2) from a compound of "a" intense, and salagein, "to raise a disturbance or noise";
(3) from a compound of the alpha privitive a- and selgo, or thelgo, "exciting disgust or displeasure." It evidently means conduct and character that is unbecoming, indecent, unrestrainedly shameless.
2. As Used in the New Testament: