—v.t. 1. to weaken or reduce in force, intensity, effect, quantity, or value: to attenuate desire. 2. to make thin; make slender or fine.
3. Bacteriol.,Immunol.to render less virulent, as a strain of pathogenic virus or bacterium.
4. Electronics.to decrease the amplitude of (an electronic signal).
—v.i. to become thin or fine; lessen.
—adj. 1. weakened; diminishing.
2. Bot.tapering gradually to a narrow extremity.