block out

verb4

1. •
   to prevent from entering or penetrating.

   • High-factor suncream blocks out the sun's rays.
2. •
   to prevent (a thought) from entering one's mind.

   • After finding out she had terminal cancer, she tried to block out any thoughts of her own mortality.
3. •
   to cover something, so as to make it impossible to see.
4. •
   to begin to reduce to shape; to mark out roughly; to lay out.