'blank out' definitions:

Definition of 'blank out'

(from WordNet)
verb
Be unable to remember; "I'm drawing a blank"; "You are blocking the name of your first wife!" [syn: forget, block, blank out, draw a blank] [ant: call back, call up, recall, recollect, remember, retrieve, think]
verb
Cut out, as for political reasons; "several line in the report were blanked out"