The Collaborative International Dictionary of English v.0.48:

Uphill \Up*hill"\, adv.
   Upwards on, or as on, a hillside; as, to walk uphill.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Uphill \Up"hill`\, a.
   1. Ascending; going up; as, an uphill road.
      [1913 Webster]

   2. Attended with labor; difficult; as, uphill work.
      [1913 Webster]

WordNet (r) 3.0 (2006):

uphill
    adv 1: against difficulties; "she was talking uphill"
    2: upward on a hill or incline; "this street lay uphill"
    adj 1: sloping upward [syn: acclivitous, rising, uphill]
    n 1: the upward slope of a hill