arduous /ärˈdū-əs/

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

ardˈuously adverb

• responsible
• responsibleness
• responsibly
• responsions
• responsive
• responsively
• responsiveness
• responsivenesses
• responsor
• responsorial
• responsorials
• responsories
• responsors
• responsory
• responsum
• respray
• resprayed
• respraying
• resprays
• ressaldar
• rest
• restaff
• restaffed
• restaffing
• restaffs