[a] ber.ga.lau a sibuk beramai-ramai; ramai sekali; kacau tidak keruan (pikiran)
It's not slang, but it's interpreted by most people slangly. Galau means hubbub, commotion, chaos (related to mind). from what I reckon, today, most people use the word to describe their state of confuseness which is exactly correct. Still, more people(and that includes me) use it to express a sort of loneliness, melancholiness, angriness or just plain pathetic stuffs in the daily life of one.
It's been such a phenomenon to me to actually realize that this could spread all over the country and within a year everybody seems to agree with the new other meaning of the word. All I can remember is that there was somebody used the word on twitter and everyone(including me) starts doing so. It gives me an idea of how effectively you can make something cool out of social medias/networks. All it takes are just a few hundreds of retweeting followers and You might make another word popular and overused 🙂
Another Slang I love would be unyu.
-what the heck
The word is not in kbbi, I googled it to find the real/former meaning of the word. An account in twitter @faktanya explained that in sansekertan, it'd mean Anjing. Someone told me it was an acronym UNYU, you and why you.
All I know it means somewhat cute.
Man, Slang words always get me curious :3