attĕnŭātĭo

ōnis, f.

attenuo

I. a diminishing, lessening (only in the two foll. exs.): attenuatio suspitionis, Auct. ad Her. 2, 2: verborum attenuatio, id. ib. 4, 11; cf. attenuatus.
Lewis & Short
A Latin Dictionary, 1879
An open-access project