The Collaborative International Dictionary of English v.0.48:

fingerpaint \fingerpaint\, finger paint \finger paint\n.
   A type of paint having the consistency of a thin paste or
   jelly, which is applied to a surface by dipping fingers into
   the paint and smearing the paint on the surface, usually in
   artistic patterns. It is used primarily by children.
   [PJC] finger-paint

WordNet (r) 3.0 (2006):

finger paint
    n 1: paint that has the consistency of jelly [syn: finger
         paint, fingerpaint]