madcap
mad-cap
adjective
Characterised by wild, reckless, and often amusingly foolish behaviour.
"They embarked on a madcap adventure."
noun
A person who behaves in a wild, reckless, or foolish way.
"He was known as a lovable madcap."
Thesaurus
Synonyms: tearaway, incautious, hotheaded, impetuous, impulsive, brainish, daredevil, harum-scarum, swashbuckler, lunatic, hothead