Total vocabulary has a remarkably high correlation (0.8-0.9) with IQ scores. There are several free tests available on the Internet to gauge your total vocabulary. One total-vocabulary test, the
WordSmart Challenge, may be downloaded from WordSmart. Their
Scoring Chart.equates a WordSmart score of 205 with a perfect score of 800 on the post-1995 recentered SAT, and assigns WordSmart scores of 209 to lawyers, 213 to college professors, 219 to editors, and 236 to major executives.
The Magus test is also free. Another good total-vocabulary test is
Tejay Sener's 600-Word Vocabulary Test. Darryl Miyaguchi has been good enough to point out that this 600-word vocabulary test wasn't actually written by Tejay, but was taken from another source ("The Joy of Lex", by Gyles Brandreth, which Tejay quotes). So It's Tejay's test in the sense that he has sponsored it and adapted it for the web. Thanks, Darryl. And thanks, Tejay, for the test, which wouldn't be available to us if it weren't for your efforts.
    As anyone who's tried it can attest, this test has a very high ceiling. At the same time, there are enough questions on the test that it covers a broad range of words. The top scorers on this test may be found at:
Tejay Sener's Great List of Literati.. I have provided the following
Definitions for the 600-Word Vocabulary Test, to spare the test-taker the onus of checking the definitions in a dictionary. A related vocabulary test which presents antonyms and synonyms is
Peter Schmies' Word Classification Test, which can be taken online. A discussion of both these tests, including a score-distribution histogram, an estimation of its standard deviation, and a free dictionary/thesuarus containing the
10,000 Most Difficult Words is discussed at:
Word-Classification-Test Histogram and Standard Deviation.
Vocabulary tests

    An expanded discussion of the role of vocabulary in intelligence measurement may be found at
the role of vocabulary in IQ testing, together with a discussion ofvocabulary tests, measuring the size of your vocabulary, and vocabulary augmentation