Pronunciation (UK) IPA (key): /ˈdɑːstədli/ or /ˈdæstədli/ (US) IPA (key): /ˈdæstɚdli/ Audio (UK)(file) Adjective Positive dastardly Comparative more dastardly Superlative most dastardly Dastardly means to show a lack of courage. Your dastardly act should cause you great shame!Wikiwand - on Seamless Wikipedia browsing. On steroids.Remove ads