The Collaborative International Dictionary of English v.0.48:
greaseproof \grease"proof\ adj. resistant to penetration by grease or oil or wax; as, greaseproof wrapping paper. [WordNet 1.5]WordNet (r) 3.0 (2006):
greaseproof adj 1: resistant to penetration by grease or oil or wax; "greaseproof wrapping paper"