The Collaborative International Dictionary of English v.0.48:

Sideling \Side"ling\, adv. [OE. sideling, fr. side side. See
   Side, and cf. Sidelong, Headlong.]
   Sidelong; on the side; laterally; also, obliquely; askew.
   [1913 Webster]

         A fellow nailed up maps . . . some sideling, and others
         upside down.                             --Swift.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Sideling \Side"ling\, a.
   Inclining to one side; directed toward one side; sloping;
   inclined; as, sideling ground.
   [1913 Webster]