/pin"up'/ , n.
1. a large photograph, as of a sexually attractive person, suitable for pinning on a wall.
2. a person in such a photograph.
3. a device or fixture that is fastened to a wall, as a lamp.
adj.
4. of, pertaining to, or appearing in a pinup: a pinup girl.
5. designed or suitable for hanging or fastening on a wall: a pinup lamp.
Also, pin-up .
[ 1670-80 for general senses; 1940-45 as photograph of a pretty woman; n., adj. use of pin up ]