What is Oily ?
Oily is (adj) 1. containing oil Oily food makes me feel sick. The tank was full of some oily liquid. 2. covered with oil He used an old oily rag to clean his motorbike. 3. (of manner.) too polite and insincere I can’t stand her oily manner. He smiled an oily smile. (NOTE: oilier oiliest)
source: Easier English, Student Dictionary Upper Intermediate Level