mockers - In the parallel, 2Pe 3:3, the same Greek is translated, “scoffers.” The word is found nowhere else in the New Testament. How Alford can deny that 2Pe 3:2, 2Pe 3:3 is referred to (at least in part), I cannot imagine, seeing that Jude quotes the very words of Peter as the words which the apostles used to speak to his (Jude’s) readers.
walk after their own ungodly lusts - literally, “after (according to) their own lusts of ungodliness.”