The regex will either match luscious and lucious only and nothing else.
No, it's not equivalent to luscious
luscious is pretty much equivalent to: if luscious isin $1- or luscious iswm $1-
I wouldn't recommend that you use the wild-card (iswm) or the isin operator, because if someone says the adverb "lusciously," he or she will get k-lined!
Your initial text event was okay, because you didn't insert the asterisk at both ends of the word luscious. But it'll still match for one word, and not "lucious"