John Gill Commentary 2 Peter 2:18

"For, uttering great swelling [words] of vanity, they entice in the lusts of the flesh, by lasciviousness, those who are just escaping from them that live in error;" — 2 Peter 2:18 (ASV)

For when they speak great swelling [words] of vanity
Marvellous things against the God of gods, great things and blasphemies against God, his name, his tabernacle, and his saints; see (Daniel 11:36) (Revelation 13:5Revelation 13:6) ; or against men, dominions, and dignities, (2 Peter 2:10) ;

or it may design their self-applauses and vain glorying in themselves, and their empty boast of knowledge and learning; and also express the windiness of their doctrines, and the bombast style, and high flown strains of rhetoric in which they were delivered;

as likewise the flattering titles they bestowed on men for the sake of their own worldly interest and advantage; see (Jude 1:16) and hereby

they allure, through the lusts of the flesh, [through much]
wantonness, those that were clean escaped from them who live in error :
that is, from those who lived in the error of Heathenism or Judaism, from whom, and which, they were clean escaped; or truly, really, and entirely delivered, being fully convinced of the falsity thereof, and of the truth of the Christian religion; though some copies, as the Alexandrian, and two of Beza's, and two of Stephens's, read, not (ontwv) , "truly", but (oligwv) , "a little"; and the Vulgate Latin version renders it, "a very little"; to which agrees the Complutensian edition; and the Syriac version renders it "in a few words", or "almost"; and according to the Ethiopic version, "a few persons" are designed;

but be they more or less, and truly, or but a little, and for a little while, or almost, escaped from their former errors, in which they were brought up, and lived; yet by the carnal lusts and liberties, lasciviousness and wantonness, which these false teachers indulged, they were allured, ensnared, and drawn by them into their wicked principles and practices.