Entirely Hex Words

aa, ab, aba, abaca, abba, abbe, abed, accede, acceded, ace, aced, ad, add, added, ae, aff, ba, baa, baaed, baba, babe, bacca, baccae, bad, bade, baff, baffed, be, bead, beaded, bed, bedad, bedded, bee, beebee, beef, beefed, cab, cabbed, caca, cad, cade, caeca, caf, cafe, caff, ceca, cede, ceded, cee, da, dab, dabbed, dace, dad, dada, daff, daffed, de, dead, deaf, deb, decade, decaf, dee, deed, deeded, def, deface, defaced, ebb, ebbed, ed, ef, eff, efface, effaced, fa, fab, facade, face, faced, fad, fade, faded, faff, faffed, fe, fed, fee, feeb, feed

My favorite: effedface. Though 0xeffdface would fit in an int. 0xFADEDBEE 0xBEDAFFED 0xDECAFBAE 0xFEEDFACE 0xDEFACADE