Attenuant \At*ten"u*ant\, a. [L. attenuans, p. pr. of attenuare:
cf. F. att['e]nuant. See {Attenuate}.]
Making thin, as fluids; diluting; rendering less dense and
viscid; diluent. -- n. (Med.) A medicine that thins or
dilutes the fluids; a diluent.
[1913 Webster]