Replacing with nothing really is the idiomatic 'delete this pattern' operation.
:%s/pattern//g
If you want to blank all lines that contain a pattern, like in your example, the obvious solution is to add wildcard matches around the pattern.
:%s/.*pattern.*//
An alternative is to use :global
with a normal mode or Ex command. These two achieve the same thing:
:g/pattern/normal! S
:g/pattern/delete|put! _
By the way, while I don't recommend using abbreviated command names in scripts or in code that other people might see, I think it's fine to use them interactively. Thus I tend to abbreviate such commands as :g/pattern/norm! S
and :g/pattern/d|pu!_
.