Aggrandize is a transitive verb, used with an object, that means to cause something or someone to be or appear to be magnified or greater. It can be in relation to size, quantity, wealth, or prominence.
One of the more common ways this word is used today is paired with the prefix self-. To self-aggrandize is to make oneself appear to be more important or bigger. One can be a self-aggrandizer.
The noun form is aggrandizement and a person who aggrandizes something is an aggrandizer.
Aggrandize is a word that changes outside the United States. It becomes aggrandise, aggrandising, and aggradisement. The spelling also changes through all forms if self-aggrandise. It should be noted that in British dictionaries the -ize ending is the formal entry while the -ise ending is listed as an alternative spelling.