The Collaborative International Dictionary of English v.0.48:

Penniless \Pen"ni*less\, a. [From Penny.]
   Destitute of money; impecunious; poor. -- Pen"ni*less*ness,
   n.
   [1913 Webster]

WordNet (r) 3.0 (2006):

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