One who has a compulsive and unrelenting need to work. (noun)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "workaholic" in a sentence
"The term workaholic very aptly describes this addiction."
"The leisure class has given way to what I call the workaholic wealthy -- an elite of BlackBerry-crazed, network-obsessed, peripatetic travelers who have to keep scrambling to maintain their place in life."
"Your inner compulsive workaholic is fooling you again."