Pretend to be inaccessible or uninterested; act coy, especially with the opposite sex. For example, I know he has no appointments tomorrow; he's just playing hard to get, or Nicole is very popular, perhaps because she plays hard to get. [Mid-1900s]
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.