A pill or tablet that contains the drug methaqualone.
From m-w.com (format adapted to match dictionary.com):
2 a : sexually unchaste or licentious b : OBSCENE, VULGAR
Therefore, untoward behavior is lewd, not lude. I’ve seen this mistake at least two different places in the past week or so, and for whatever reason, it’s really kinda buggin’ me. :-P
Just thought I’d share...