GLAG Share definition Flag Internet acronym for "giggling like a girl". Synonomous with LOL, ROFL, and other similar acronyms. Person 1: You're a stupid fish vagina! Persong 2: GLAG! GLAG by Alexis Lover July 31, 2005 Words you can keep railfan mug chonk mug chud mug based mug 67 mug slime mug mogging mug chopped mug thot mug glazing mug huzz mug yams mug larp mug unc mug cracked mug simp mug baddie mug bop mug lolcow mug