the word 'thusly' is a modern english formation, created by adding the productive adverbial suffix '-ly' to the pre-existing adverb 'thus'. the base word 'thus' originates from old english þus, which is of germanic descent, related to old frisian and old saxon thus, meaning 'in this way'. the addition of '-ly', itself from old english -līċe, is a redundant morphological process, as 'thus' is already an adverb. this formation, emerging in the 19th century, is often regarded as nonstandard or used for humorous or emphatic effect, illustrating a linguistic phenomenon where speakers analogically extend regular patterns (like adverb formation with '-ly') to irregular forms.

Structure: thus (in this way) + ly (adverb-forming suffix) - thus: from old english þus, of germanic origin; an adverb meaning 'in this way'. - ly: from old english -līċe, an adverb-forming suffix.