"heavy infantry" is a correct and usable phrase in written English.
It refers to soldiers who are equipped with heavier armor and weapons than regular infantry. An example of using this phrase in a sentence could be: "The heavy infantry unit marched in formation, their clanking armor and large shields intimidating their enemies."
The used-remote-control market was being pulverized beneath the tread of the advancing heavy infantry.
Robert planned to use the trees there to funnel any attack into his heavy infantry and freshly dug anticavalry ditches.
Seven legions in three lines, comprising about 25,000 heavy infantry, occupied a mile and a half of front.
By classical times, breastplates of bronze, at first beaten and then cast to the warrior's individual shape, had become commonplace among heavy infantry and elite cavalry.
Still, it is true that never during classical antiquity did cavalry succeed in replacing the formations of heavy infantry that remained the backbone of every army.
As a formation whose main power consisted of its heavy infantry, the legion remained unmatched until the introduction of firearms and beyond.
Skirmishers engaged before the heavy infantry pushed slowly together from both sides; Demetrius drove forward, with the elite of the Antigonid cavalry, from the right flank.
The 3,600 heavy infantry were supported by enough cavalry and light infantry to bring the legion's strength up to 6,000 men.
By classical times, breastplates of bronze, at first beaten and then cast to the warrior's individual shape, were commonplace among heavy infantry and elite cavalry.
The Thebans and Phliasians were asked for money, the Eleans for hulls as well; while Corinth herself furnished thirty ships and three thousand heavy infantry.
The basic weapon for this formation was a thrusting spear called the hasta; from this the heavy infantry derived its name, hastati, retaining it even after Rome abandoned the phalanx for the more flexible legion.
