A motorcyclist, especially a member of a motorcycle gang.(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 "biker" in a sentence
"When you hear the term biker babes, the images that fill your mind may include bleach blond hair and the scant use of finely crafted leather bikinis."
"Mountain biker Alison Dunlap won 2001 world title days after attack."
"As an avid mountain biker and swimmer, I find the following research to be fascinating."