The Collaborative International Dictionary of English v.0.48:
Imparipinnate \Im*par"i*pin"nate\, a. [L. impar unequal + E. pinnate.] (Bot.) Pinnate with a single terminal leaflet. [1913 Webster]WordNet (r) 3.0 (2006):
imparipinnate adj 1: (a leaf shape) pinnate with a single leaflet at the apex [syn: odd-pinnate, imparipinnate]