Short for "Not Safe For 56 Kbaud Modems". Tagline abbreviation added to an internet forum post (or other missive) to warn of massive attachment size, which a normal analog phone modem may be incapable of coping with.
Click Here: Britney Spears Sucking Face With Madonna. NSF56K!
by 1Spectre4U December 02, 2003
Not Safe For 56K. A phone line that isn't good enough to get the full connection speed of a 56K modem.
I moved out into the country, and they gave me a NSF56K line!
by NSFMR2K December 02, 2003

Free Daily Email

Type your email address below to get our free Urban Word of the Day every morning!

Emails are sent from We'll never spam you.