The Collaborative International Dictionary of English v.0.48:

Necessitous \Ne*ces"si*tous\, a. [Cf. F. n['e]cessiteux.]
   1. Very needy or indigent; pressed with poverty.
      [1913 Webster]

            Necessitous heirs and penurious parents.
                                                  --Arbuthnot.
      [1913 Webster]

   2. Narrow; destitute; pinching; pinched; as, necessitous
      circumstances.
      [1913 Webster] -- Ne*ces"si*tous*ly, adv. --
      Ne*ces"si*tous*ness, n.
      [1913 Webster]

WordNet (r) 3.0 (2006):

necessitous
    adj 1: poor enough to need help from others [syn: destitute,
           impoverished, indigent, necessitous, needy,
           poverty-stricken]