。
I'm not talking about anyone in particular.
Literal
Particularly specific person [object-を] pointing say-ing [explanatory-の] is-not.
別に特定の人をさして言っているのではない — 'it's not that I'm pointing at a specific person and saying it.' さす (指す) means 'to point at/indicate.' The のではない construction negates the underlying explanation. A defensive clarification, perhaps after a general comment was taken personally.