Ng

[Justin Bieber]

No Good.

[Jessica]

An abbreviation for No Good that was made popular by the anime Super Milk Chan. Especially one entire episode called NG wich acts as a blooper reel and we are shown outtakes or NG takes of scenes that where used many times in the series.
It also is not meant to gramerticaly correct. IE in the quote below the woman says Absouletly NG, now, in english saying Absouletly No Good in the context of refusing a proposition would be incorrect. Thus, we can assume, that its not meant to be taken literal.