←
Old English -tiġ (inherited)
←
Middle English -ty (inherited)
←
Middle English -te (inherited)
←
Old French -te (derived)
←
West Frisian -tich (cognate)
←
Proto-Germanic *teguz (mention)
←
Proto-Indo-European *deḱ- (inherited)
←
Proto-Indo-European *déḱm̥ (mention)
→
English -eous (mention)