Definition of "NSF"

(US) Initialism of National Science Foundation.  examples

(banking) Initialism of nonsufficient funds: the alert generated by a bounced check or an ACH transaction failure due to not enough money being in the account.  examples

(Internet, acronymy component) Initialism of not safe for [context] or initialism of not suitable for [context]: labels online content as being not appropriate for, and not to be clicked or displayed in, the named context; for example, NSFW (work), NSFL (life or lunch), NSFM (minors).  examples