Sniper
A rifleman who fires from a concealed place, esp a military marksman who fires from cover, usually at long ranges at individual enemy soldiers [Dictionary.com].
A sniper is a highly trained soldier who shoots targets with modified rifles from incredibly long distances. They're also adept in stealth, camouflage, infiltration, and observation techniques.
Military snipers are used in a variety of missions on the battlefield, and the sniper's primary mission has nothing to do with pulling a trigger. The main battlefield role of the sniper is reconnaissance. Because snipers are masters of stealth, they are perfectly suited to sneak behind enemy lines to provide the command with information about the enemy's size, strength, and location.
When the mission calls for it, snipers can also dismantle and dishearten the enemy with a few well-placed rifle shots. Instead of engaging the enemy forces like traditional infantry, snipers hunt key people -- officers, pilots, armor drivers, technicians, and communications operators. With deadly shots that kill without warning, military snipers break the enemy's will and ability to fight [Howstuffworks].
"Sniper" in translation from English means "accurate shooter at flying ducks." Once upon a time in England, so-called lucky hunters. Then they began to call the Boer shooters. There were reasons for this. With their long-range rifles, the Boers got the British at any time of the day and, in the safest places. The well-known gentleman's rule "three from one match does not light up" was born there, on the British positions in the Transvaal Republic.
At night, when Her Majesty's officers gathered in a bunch and relaxed with nicotine, the Boer sniper spotted the flash of a lit match and the flame of a cigar when the first officer lit it. The second officer lit it - the match flame moved, the second cigar lit up, and the sniper took the lead to shift the fire. He lit a third and immediately received a bullet in the head [Потапов, p. 1].
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