From Longman Dictionary of Contemporary Englishblock sth↔ out1 PREVENTto stop light reaching a place There was a heavy curtain blocking out the light.2 FORGETto stop yourself thinking about something or remembering it a memory so terrible that she tried to block it out → block→ See Verb table
Examples from the Corpus
block out• But I can block everything out.• It was so horrific, I think my memory has blocked it out.• So at the Washington game two nights later I decided to block it out.• I've just blocked it out and it hasn't changed my attitude to cars, except that they're not safe enough.• Though she seemed not to notice them, apparently had the ability to block them out, even to forget about them.• She had blocked him out since his mention of the two unpublished novels.• He said it could follow an incident so dire that the mind had to block it out, sometimes along with other things.• Every word stops me turning away and closing my eyes, to block it out, to let me retreat into sleep. 