callipygian
I just remembered this word my friends & I encountered when we played Cranium a few months ago:
Main Entry: cal·li·pyg·ian
Pronunciation: “ka-l&-‘pi-j(E-)&n
Variant(s): also cal·li·py·gous /-‘pI-g&s/
Function: adjective
Etymology: Greek kallipygos, from kalli- + pygE buttocks
: having shapely buttocks
Taken from: Merriam-Webster Online Dictionary