(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.

Combat using groups of irregular, light, mobile troops within areas occupied by an enemy force, usually through hit-and-run tactics.

The use of harmful microorganisms as a weapon of war.

The use of any harmful organism (such as a bacterium or virus) as a weapon of war.

Warfare (armed conflict) between belligerents who have different strengths and weaknesses.

Warfare in which one or more combatants are irregulars (such as partisans, guerrillas or insurgents) rather than regular military forces.

The waging of war in a manner which does not use nuclear, biological, or chemical weapons. / The waging of war in set military battles, as opposed to waging guerrilla warfare or fighting insurgencies.

(idiomatic) A mentally manipulative approach to warfare involving use of techniques to demoralize or intimidate someone into surrender.

The use and management of information in pursuit of an advantage over an opponent, such as propaganda, disinformation, and gathering assurances that one's own information is accurate.

The use of nuclear weapons as weapons of war.