Fierce. From the start of this war to its end in a whimper, everything and anything the least bit non-friendly was described by the media as fierce.
What exactly would non-fierce resistance consist of? If the Battle of Kursk was "fierce", does a ragged irregular taking a pot shot with an AK-47 qualify as well?
Since the commentators don't know a Tomahawk missile from a Bradley Fighting Vehicle, it all looks "fierce" to them.
"Fierce" and "determined." Don't forget "determined."