From The Collaborative International Dictionary of English v.0.48:
Imputable \Im*put"a*ble\, a. [Cf. F. imputable.] [1913 Webster] 1. That may be imputed; capable of being imputed; chargeable; ascribable; attributable; referable. [1913 Webster]
A prince whose political vices, at least, were imputable to mental incapacity. --Prescott. [1913 Webster]
2. Accusable; culpable. [R.] [1913 Webster]
The fault lies at his door, and she is no wise imputable. --Ayliffe. [1913 Webster]