The definition of out of pocket is something that you had to pay for yourself, expenses incurred that you were responsible for or money losses you had to bear.(adjective)
When you go on a business trip but decide to take yourself out to dinner and pay on your own, the cost of the dinner is an example of an out of pocket expense.
See out-of-pocket in Webster's New World College Dictionary
See out-of-pocket in American Heritage Dictionary 4
Learn more about out-of-pocket