Green’s Dictionary of Slang

blank v.2

[SE blank out, to erase; note baseball jargon blank, to retire a team without letting them score]

1. to ignore.

[UK]G.F. Newman You Flash Bastard 23: Had Rosi been available, it was unlikely he would have blanked Paul Rosi, unless he had an ulterior motive for so doing.
[UK]J. Campbell Gate Fever 16: To blank [...] to ignore.
[UK]D. Widgery Some Lives! 3: So I just blanks him and he starts giving me licks.
[UK]N. Griffiths Stump 74: Why the friggin deadhead, lar? I mean, you’ve been blankin me since.
[UK]A. Wheatle Dirty South 32: White trash girls never blanked you on the road.
[Scot]T. Black ‘Killing Time in Las Vegas’ in Killing Time in Las Vegas [ebook] He blanked me big time as he popped an iPad on the desk.

2. to wipe out, to reject.

[UK]G. Burn Happy Like Murderers 57: She blanked this for many years. Her memories were revived years later.
[UK]N. Barlay Hooky Gear 300: I try an blank it.

3. to overlook.

[US]B. Hamper Rivethead (1992) 69: I totally blanked on the biggest, baddest, meanest minus of them all: the unemployment line.

4. to absent oneself temporarily from consciousness, to ‘space out’.

[UK]A. Hollinghurst Swimming Pool Library 240: I was trying to decide whether or not he was looking at me, whether this lull was [...] one of Charles's unsignalled abstentions, a mental treading water, 'blanking' as he called it.

In phrases

blank out (v.)

1. to render unconscious.

[US]R. Chandler Long Good-Bye 207: We’ve been through this before – that night when the gun went off. I suppose the seconal blanked you out too. You sounded sober enough. But now you pretend not to remember.

2. to become (temporarily) unconscious and/or uncomprehending.

[UK]J.W. Warden Wayward Legionnaire 114: My mind had blanked out completely [...] I was no longer aware that I was in the Legion, or even in Algeria. [...] I had become delirious .
[US]J. Stahl Plainclothes Naked (2002) 19: ‘We gotta split,’ Tony announced, as if he hadn’t just blanked out.
blank up (v.) [to render one’s victim ‘blank’]

(US black) to trick, to murder.

[US]C. Major Juba to Jive 41: Blanked up [...] (1980s–1990s) to be tricked or even murdered.