pennyroyal /pen-i-roiˈəl/

1. A species of mint (Mentha pulegium) once valued in medicine
2. A related plant, Hedeoma pulegioides (US)

• swamp fevers
• swamp gas
• swamp gases
• swampier
• swampiest
• swampiness
• swampinesses
• swamping
• swampland
• swamplands
• swamp oak
• swamp oaks
• swamps
• swampy
• swan
• swan about
• swan around
• swan dive
• swan dives
• Swanee whistle
• swang
• swan-geese
• swan-goose
• swanherd
• swanherds