1. Requiring great effort
   "a hard-fought primary"

See also: difficult, hard

• ground sloth
• ground snake
• ground squirrel
• ground state
• ground stroke
• ground substance
• ground swell
• ground tackle
• ground water
• ground wave
• ground zero
• ground-controlled approach
• ground-effect machine
• ground-emplaced mine
• ground-floor
• ground-hugging
• ground-service crew
• ground-shaker
• groundball
• groundberry
• groundbreaker
• groundbreaking
• groundbreaking ceremony
• groundcover
• grounder