wilful vs headstrong

wilful and headstrong both are adjectives.

Word	Noun	Adjective	Verb	Adverb
wilful	No	Yes	No	No
headstrong	No	Yes	No	No

As adjectives, wilful and headstrong are synonyms defined as:

wilful and headstrong: habitually disposed to disobedience and opposition

Other synonyms of wilful include froward, self-willed, willful.

wilful (adjective)	headstrong (adjective)
habitually disposed to disobedience and opposition	habitually disposed to disobedience and opposition
done by design