the word 'wilfully' is built upon the old english noun will, which denoted desire, intention, or the faculty of volition. this term traces back to the proto-germanic weljaną and further to the proto-indo-european root welh₁-, meaning "to wish, to will". the suffix -ful was added to form the adjective 'wilful', literally meaning "full of one's own will", thus characterizing someone as determined, obstinate, or intentional. the final adverbial suffix -ly then modifies the adjective to describe the manner of an action. the modern sense of 'wilfully' thus logically evolves from the core idea of acting in a manner characterized by one's own strong desire or intention, often with a connotation of disregarding external rules or advice.

Structure: will (desire, intention) + ful (full of) + ly (adverb suffix) - will: from old english will, meaning "desire, intention, determination". functions as the core root conveying volition. - ful: from old english -ful, a suffix meaning "full of" or "characterized by". functions as an adjective-forming suffix. - ly: from old english -līce, a suffix forming adverbs from adjectives. functions as an adverb-forming suffix.