Yes. Create a filter where the “By log tag” field is
^(?!.*(MYTAG)).*$
where MYTAG is the tag you don’t want to see. I am not a regexp expert (a “regexpert”? 😉 ) so there may be a simpler way to do that negation, but I just tried that and it works.
You can play around with the filter in the field just above the Log Cat message area, by entering filter strings there, like this:
tag:^(?!.*(DeskClock|dalvik|wpa)).*$
which will show all messages except tags “DeskClock”, “dalvik”, and “wpa”.