bes Share definition Flag A tagalog slang that is actually a shortcut for bestfriend. But usually, Filipino's just use this for anyone and not just their friends. Just like how "fam" is used. Someone: Bes, what time is it? Anyone: Idk bes, I left my phone at home. bes by Samwan Ober Da Reynbow September 14, 2016 Get the bes mug.Get the mug.