WordNet
n. fire designed to disturb the rest of enemy troops and to curtail movement and to lower enemy morale
Wikipedia
Harassing fire is a form of psychological warfare in which an enemy force is subjected to random, unpredictable and intermittent small-arms or artillery fire over an extended period of time (usually at night and times of low conflict intensity) in an effort to undermine morale, increase the enemy's stress levels and deny them the opportunity for sleep, rest and resupply. This lowers the enemy's overall readiness and fighting ability, acting as a force multiplier for the harassing force.
As the name suggests, harassing fire is undertaken as an extreme form of nuisance without a major effort to produce significant casualties or to support a larger attack. The intent is to merely ensure the enemy can never fully rest or attend to non-combat related tasks and must always be alert and in cover from incoming fire. For this reason, harassing fire is often conducted at night (or around the clock if resources allow) and by a small number of guns or artillery pieces rather than the whole contingent. The denial of sleep and constant alert state it induces is physically and psychologically unsustainable by infantry forces for any length of time, and eventually causes severe degenerative stress and degradation of the force's combat abilities. For this reason, it has been a standard and efficacious tactic used since the introduction of the projectile weapon.
Usage examples of "harassing fire".
We've been keeping them under light harassing fire everywhere in the district except here.
Bob's platoon had been surrounded, and he manned a machine-gun, hitting the Germans with harassing fire until the platoon broke through the encirclement.
Usually the NATO forces would save their harassing fire for the forward trench line or the massed Soviet armor near the front.
Somewhere off in the trees, a machine gun opened up with harassing fire.
No reply from the battlements, no harassing fire hoping to take its toll.
Companies in the front line were replaced as often as possible to relieve them from the constant harassing fire of the enemy.
He spun the steering wheel through a tight right turn and peppered the truck ahead with more harassing fire.
The gunners had shortened their range to enfilade the attackers, and the Yankees close to the Legion crept back to the tree line to begin their harassing fire again.