The Collaborative International Dictionary of English v.0.48:

Hard \Hard\, adv. [OE. harde, AS. hearde.]
   1. With pressure; with urgency; hence, diligently; earnestly.
      [1913 Webster]

            And prayed so hard for mercy from the prince.
                                                  --Dryden.
      [1913 Webster]

            My father
            Is hard at study; pray now, rest yourself. --Shak.
      [1913 Webster]

   2. With difficulty; as, the vehicle moves hard.
      [1913 Webster]

   3. Uneasily; vexatiously; slowly. --Shak.
      [1913 Webster]

   4. So as to raise difficulties. "The question is hard set."
      --Sir T. Browne.
      [1913 Webster]

   5. With tension or strain of the powers; violently; with
      force; tempestuously; vehemently; vigorously;
      energetically; as, to press, to blow, to rain hard; hence,
      rapidly; nimbly; as, to run hard.
      [1913 Webster]

   6. Close or near.
      [1913 Webster]

            Whose house joined hard to the synagogue. --Acts
                                                  xviii. 7.
      [1913 Webster]

   Hard by, near by; close at hand; not far off. "Hard by a
      cottage chimney smokes." --Milton.

   Hard pushed, Hard run, greatly pressed; as, he was hard
      pushed or hard run for time, money, etc. [Colloq.]

   Hard up, closely pressed by want or necessity; without
      money or resources; as, hard up for amusements. [Slang]
      [1913 Webster]

   Note: Hard in nautical language is often joined to words of
         command to the helmsman, denoting that the order should
         be carried out with the utmost energy, or that the helm
         should be put, in the direction indicated, to the
         extreme limit, as, Hard aport! Hard astarboard! Hard
         alee! Hard aweather! Hard up!
         Hard is also often used in composition with a
         participle; as, hard-baked; hard-earned; hard-featured;
         hard-working; hard-won.
         [1913 Webster]

WordNet (r) 3.0 (2006):

hard up
    adj 1: not having enough money to pay for necessities [syn:
           hard up, impecunious, in straitened
           circumstances(p), penniless, penurious, pinched]

Moby Thesaurus II by Grady Ward, 1.0:

35 Moby Thesaurus words for "hard up":
   badly off, desperate, distressed, down to bedrock, embarrassed,
   feeling the pinch, hard pressed, ill off, impecunious,
   in Queer Street, in desperate straits, in extremis, in extremities,
   in narrow circumstances, in reduced circumstances,
   in straitened circumstances, land-poor, narrow, on the edge,
   out of pocket, pinched, poor, poorly off, reduced, short,
   short of cash, short of funds, short of money, sorely pressed,
   squeezed, straitened, strapped, unmoneyed, unprosperous,
   up against it