Meaning of “block sth out” - Learner’s Dictionary

block sth out

phrasal verb with block us uk /blɒk/ verb [ T ]

to try to stop yourself thinking about something unpleasant:

I've blocked out memories of the accident.

to stop light or noise passing through something:

Most sunscreens block out UVB radiation.

(Definition of “block sth out” from the Cambridge Learner’s Dictionary © Cambridge University Press)