pin-up n 1. informal a. a picture of a sexually attractive person, esp when partially or totally undressedb. (as modifier): a pin-up magazine. 2. slang a person who has appeared in such a picture 3. a photograph of a famous personality 4. (modifier) US designed to be hung from a wall: a pin-up lamp. Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014