turbidity, mixing
淆 centers on a state of being mixed up and unclear, like muddy water where different things are blended together into a turbid, indistinct mass.
淆 combines 氵 (water) with 肴, which likely contributes the sound and the idea of mixing or blending, as in water becoming turbid when things are stirred together.
Water 氵 on the left and 肴 (which can suggest food or mixing) on the right: imagine stirring a pot of soup until the water becomes cloudy and all the ingredients are mixed together.
For コウ, picture a cook stirring a turbid broth: cook -> コウ, and the cook's mixing makes the water cloudy.