To turn up for an event early, then leave before everyone else gets there.
Dan turned up at 4 o clock, even though we agreed to start playing at 5, then did a Hallows.
by OiBrent October 06, 2008
Also used in JK Rowling's last Harry Potter book title.
Harry Potter and the Deathly Hallows
by cadences December 21, 2006
another term for being loose
"Damn, Matt is very hallow.I wouldn't want to touch that!"
by MCbeshin April 04, 2009