old witch grass old·witchg·rass uncommon noun 1. North American grass with slender brushy panicles; often a weed on cultivated land Synonymswitchgrasswitch grassold witchgrassold witch grasstumble grassPanicum capillare Related words Broader terms panic grass WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.
