Skt. Grammar Query

[Michael J. Sweet]

Is there a vyakarana-walla out there who could help with the following
perplexity?:  In the Siddhanta-Kaumadi on Pa. VI.3.75 (#759 om Vasu, vol.
1.448), there is a list of words in which the negative particle remains
unchanged, among which is *napumsaka*.  The author explains this as: "na
stripumsayoh pumsakabhavo nipatanat"  Vasu does not translate this!  Any
suggestions as to the meaning of this line?  Many thanks in advance. 

                                                  Michael Sweet