The Collaborative International Dictionary of English v.0.48:
apotropaic \ap`o*tro*pa"ic\ ([a^]p`[-o]*tr[=o]*p[=a]"[i^]k), n. [Gr. 'apotro`paios averting evil.] Intended to protect from evil. [PJC]WordNet (r) 3.0 (2006):
apotropaic adj 1: having the power to prevent evil or bad luck