Attenuate At*ten"u*ate, v. t. [imp. & p. p. Attenuated; p. pr. & vb. n. Attenuating.] [L. attenuatus, p. p. of attenuare; ad + tenuare to make thin, tenuis thin. See Thin.] 1. To make thin or slender, as by mechanical or chemical action upon inanimate objects, or by the effects of starvation, disease, etc., upon living bodies. 2. To make thin or less consistent; to render less viscid or dense; to rarefy. Specifically: To subtilize, as the humors of the body, or to break them into finer parts. 3. To lessen the amount, force, or value of; to make less complex; to weaken. To undersell our rivals . . . has led the manufacturer to . . . attenuate his processes, in the allotment of tasks, to an extreme point. --I. Taylor. We may reject and reject till we attenuate history into sapless meagerness. --Sir F. Palgrave.