trench warfare

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun uncountable Warfare in which opposing sides occupy trenches and repeatedly fire at one another; usually involving high casualty rates over a long period of time.
• noun uncountable, by extension, euphemistic Fighting of any sort which offers no hope of ending soon.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a struggle (usually prolonged) between competing entities in which neither side is able to win
• noun a type of armed combat in which the opposing troops fight from trenches that face each other