incorrigible
I realize that I'm an incorrigibly frivolous person.
Not only is he incorrigibly modest, but he’s also very kind.
Their daughter is an incorrigibly curious nine-year-old.
SMART Vocabulary: related words and phrases Strong-willed
adamancy
adamant
adamantine
adamantly
aggressive
grittily
gutsily
gutsy
gutty
hard-boiled
pertinaciously
pigheaded
pigheadedly
purposeful
purposefully
ultra-serious
unbending
unbroken
undaunted
unmovable
You can also find related words, phrases, and synonyms in the topics:
Bad and wrong behaviour