Added 10 October 2026 arduousness /ˈɑːdjuːəsnəs/ noun Categories: Describing WordsObscure Words noun ! Definition from WordNet 3.1, Princeton University. Pronunciation from Wiktionary, via Kaikki.org. More about arduousness at Wordnik → Where our words come from → Extreme effortfulness. Related Words: strenuousnessdifficultyenormitymagnitudearduitypainfulnessburdensomenesslaboriousnessasperityonerousnessstrenuositydifficultness Back to today's word