1. The tendency to speak or write of oneself excessively and boastfully.
2. An inflated sense of one's own importance; conceit. See synonyms at conceit.

[EGO + -tism (as in NEPOTISM).]

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.