。
If she's not exactly stingy, she's certainly thrifty.
Literal
She [topic-は] stingy [quotative-と] not-saying-even-if frugal-person is.
The pattern ~と言わないまでも ('if not exactly X, at least...') is a tactful hedge: it acknowledges that calling someone X would be too strong, and then offers a milder alternative. The まで in 言わないまでも literally means 'not going as far as to say,' with も adding the concessive flavor — 'even if not.' The contrast here is between けち ('stingy, miserly,' a clearly negative word) and 倹約家 ('frugal person, thrifty saver,' a neutral or even positive label). The whole sentence is the verbal equivalent of softening a sharp judgment.