The Collaborative International Dictionary of English v.0.48:

Purposeful \Pur"pose*ful\, a.
   Important; material. "Purposeful accounts." --Tylor. --
   Pur"pose*ful*ly, adv.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

meaningful \meaningful\ adj.
   Having a meaning or purpose; having significance; as, a
   meaningful explanation; a meaningful discussion; a meaningful
   pause; to live a meaningful life. Opposite of meaningless.
   [Narrower terms: comprehensible, understandable;
   indicative, significative, suggestive ; {meaty, substantive
   ; {purposeful] Also See: purposeful, significant,
   important.
   [WordNet 1.5]

WordNet (r) 3.0 (2006):

purposeful
    adj 1: serving as or indicating the existence of a purpose or
           goal [ant: purposeless]
    2: having meaning through having an aim; "led a happy purposeful
       life"