In this question on Server Fault, the asker says "And it works fine, but that's a ponctual solution..." and corrects himself in a comment, using "punctual".

I've only ever used "punctual" to mean "on time." Can it also mean "ad hoc"?

From dict punctual:

From The Collaborative International Dictionary of English v.0.48 [gcide]:

Punctual \Punc"tu*al, a. [F. ponctuel (cf. Sp. puntual, It. puntuale), from L. punctum point. See {Point}.] 1. Consisting in a point; limited to a point; unextended. [R.] "This punctual spot." --Milton. [1913 Webster]

         The theory of the punctual existence of the soul. --

                                                Krauth.

   [1913 Webster]