i-adjective
Jocular, archaic word formed as a play on 面白い (おもしろい). Used humorously to mean 'interesting' or 'amusing'.
「面黒い」は、昔の人が面白いをもじって使った言葉らしい。
It seems that 面黒い was a word people used in the past as a playful twist on 面白い.
i-adjective
Archaic, ironic or opposite meaning of 面白い. Rarely used; the humorous twist can imply the opposite of interesting.
江戸時代の洒落本に「面黒い」を退屈な意味で使った例がある。
There is an example in an Edo-period humorous book where 面黒い is used to mean boring.