The Collaborative International Dictionary of English v.0.48:

Moky \Mo"ky\, a. [Cf. Icel. m["o]kkvi cloud, mist, m["o]kkr a
   dense cloud, W. mwg smoke, and E. muggy, muck.]
   Misty; dark; murky; muggy. [Obs.]
   [1913 Webster]