Wiktionary
pin up
vb. (context transitive English) To put (e.g. a sheet of paper) on display, using a pin.
WordNet
pin up
v. attach with or as if with a pin; "pin up a picture" [syn: pin down]
Usage examples of "pin up".
King Shrewd fought for this lucidity He held the pin up and looked at Regal with a shadow of his old calculating glance.
He watched her pin up her hair, her movements neat, precise, though there were shadows under her eyes.