- fog, fogginess, murk, murkiness - an atmosphere in which visibility is reduced because of a cloud of some substance
--1 is a kind of atmosphere, atmospheric state
--1 has particulars: fug - indistinctness, blurriness, fogginess, fuzziness - the quality of being indistinct
--2 is a kind of opacity, opaqueness
--2 has particulars: dimness, faintness