TND
TND is an acronym for "Totally Nice Day"[1], and "Tuesday Night Drinks"[2].
It's also an abbreviation for "Total Nigger Death"[3], an old 4chan copypasta originated from (You guessed it!) /pol/. It has been adopted by soyteens to have a common slang. Some leftist fags derived it to "Total Nazi Death", but this didn't change its origin.