Oh, and I forgot the OED...
drop dead: a slang (orig. U.S.) exclamation expressing emphatic dislike or scorn of the person addressed.
drop-dead
A. adj.
1. Stunning, striking, exceptional; breathtaking, heart-stopping.
2. Chiefly Business. Designating the latest date or time by which a task must be completed or a result achieved.
B. adv. As an intensifier modifying an adjective, freq. emphasizing physical attractiveness: extremely; strikingly, astonishingly, breathtakingly. Freq. in drop-dead gorgeous.
... and the OALD:
drop dead adverb(informal) used before an adjective to emphasize that sb/sth is attractive in a very noticeable way:
a drop-dead gorgeous Hollywood star
![Tongue Tied [:S]](/emoticons/emotion-7.gif)