nonplussed

Nonplussed is an odd word. I don’t think anyone ever uses that word in an ordinary conversation. “My, you were  nonplussed when Joe told us he slaughters his own chickens.” Nope, doesn’t happen. Besides, it’s turning into a self-antonym. It’s supposed to mean “surprised and confused.” (according to the dictionary folks)
Joseph was nonplussed to discover that Lucy was his date, not the plumber come to repair the upstairs toilet, especially since she only told him after she had finished the job.
But it seems that people are now using it to mean “not disconcerted; unperturbed”
Well, that’s disconcerting!

Here are two definitions, the first from

http://dictionary.reference.com/browse/nonplussed 

and the second from

http://www.askoxford.com/concise_oed/nonplussed?view=uk

Dictionary.com Unabridged (v 1.1) – Cite This Source – Share This

non·plus  // <![CDATA[
 Audio Help   /nɒnˈplʌs, ˈnɒnplʌs/ Pronunciation Key – Show Spelled Pronunciation[non-pluhs, non-pluhs] Pronunciation Key – Show IPA Pronunciation verb, -plussed or -plused, -plus·sing or -plus·ing, noun

–verb (used with object)

1.	to render utterly perplexed; puzzle completely.

–noun

2.	a state of utter perplexity.

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[Origin: 1575–85; (n.) < L nōn plūs lit., not more, no further, i.e., a state in which nothing more can be done]

—Synonyms 1. perplex, confuse, confound, disconcert.

/nonplusst/

  • adjective 1 surprised and confused. 2 N. Amer. informal unperturbed.

  — USAGE In standard English nonplussed means ‘surprised and confused’. A new meaning, ‘not disconcerted; unperturbed’, has developed recently in North American English, probably on the assumption that the prefix non- must have a negative meaning; this is not yet accepted as standard usage.

  — ORIGIN from Latin non plus ‘not more’.
p.s. Am I the only one who wishes he could go back to vocabulary lessons in school and have fun writing those descriptive sentences? I hated it back then, but now I think it would cool to make a little story out of them.