Block out tabs containing content of YouTube (7)
I believe the answer is:
eclipse
'block' is the definition.
(I've seen this before)
'out tabs containing content of youtube' is the wordplay.
I cannot really see how this works, but
'content' could be 'lip' (lip is a kind of content) and 'lip' is present in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for eclipse that I've seen before include "Lunar or solar phenomenon" , "Block" , "Cut out" , "Lunar/solar phenomenon" , "Deprive of prominence" .)