Of, relating to, characteristic of, or causing an obsession: obsessive gambling. (adjective)
Excessive in degree or nature: an obsessive need to win. (adjective)
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 "obsessive" in a sentence
"Mr. ROTH: Oh, obsessive is a word everybody uses, but maniacal?"
"The term obsessive compulsive refers to a wide range of different behaviors."
"I only wish I could be this encyclopedic — or is the word obsessive."