Maverick
noun
An unbranded range animal.
(by extension) Anything dishonestly obtained.
(by extension) One who is unconventional or does not abide by rules.
Synonyms: heteroclite, individualist, lone gunman, nonconformist, rebel
verb
To take an unbranded range animal.
(by extension) To seize without a legal claim.
adjective
Of cattle: unbranded.
Showing independence in thoughts or actions.
“He made a maverick decision. She is such a maverick person.”