gob·smackedThere are four reasons I can think of why this is an excellent word:
adj.British slang. Utterly astounded, flabbergasted, shocked.
- It's British slang. British slang is always excellent.
- It incorporates the absolutely excellent word "gob," slang for mouth.
- It summons the excellent image of clapping one's hand to one's mouth in surprise.
- It just plain sounds excellent.