The story
- Proto-West Germanic · inherited from*fulladōn“to do fully, fulfil, complete, perfect”
- Old English · inherited fromfuldōn“to complete, perform; arrange”
- Middle English · inherited fromfuldon
- English todayfulldo
From Middle English fuldon, from Old English fuldōn (“to complete, perform; arrange”), from Proto-West Germanic *fulladōn (“to do fully, fulfil, complete, perfect”), equivalent to full- + do. Cognate with West Frisian foldwaan, Dutch voldoen, German Low German vulldoon, German volltun (“to fulldo”).
Etymology from Wiktionary, CC BY-SA 4.0.