perspicacious
Per`spi`ca´cious
Adj. 1. perspicacious - acutely insightful and wise; "much too perspicacious to be taken in by such a spurious argument"; "observant and thoughtful, he was given to asking sagacious questions"; "a source of valuable insights and sapient advice to educators"

And Perspex is UK for clear plastic used in aircraft windows.

Perspicacity was always one of my favorite words, Dr. Bill. Dunno why...just like the way it sounds, and the way it feels when you say it.

hah! ~ the word that made me, as a rebellious yoof aged 13, fall in love with English... my tutor (initials JAH and commonly known as Jahwe) patted me on the head with an enormous grin as I gave an answer to his question about Under Milk Wood and uttered in his inimitable way "Oh, perspicaceous child!" And since I had no idea if he was praising or insulting me, I went scurrying off to consult the dictionary, a habit I have never lost.

Thanks, John, for the lifelong love of literature and language to which you gave me the key. oh perspicaceous teacher :)

thanks for the morning smile, mav.