arduous /ärˈdū-əs/

1. Steep, difficult to climb
2. Difficult to accomplish
3. Laborious

ardˈuously adverb

ardˈuousness noun

• hell-boxes
• hell-bred
• hell-broth
• hell-broths
• hellcat
• melanotropins
• melanous
• melanterite
• melanterites
• melanuria
• melanurias
• melanuric
• melaphyre
• melaphyres
• melas
• Melastomaceae
• melastomaceous
• melatonin
• melatonins
• melba
• melba sauce
• melba toast
• meld
• melded
• melder