This means cutting it very short, because doing this makes it look nice, makes it cleaner and means that one is differing from the disbelievers. Umar (may Allāh be pleased with him) narrated that the Messenger of Allāh (May Allāh praise him and Peace be upon him) said, “Differ from the polytheists: leave your beards to grow and shorten your moustaches. [Reported by Muslim: 258]