ٱغْلُظْ

Appears 2 times in the Quran. (Root: غلظ)
  1. O Prophet! strive hard against the unbelievers and the hypocrites and be unyielding to them; and their abode is hell, and evil is the destination.

  2. O Prophet! strive hard against the unbelievers and the hypocrites, and be hard against them; and their abode is hell; and evil is the resort.