irrepressible

irrepressible /ˌirɪˈprɛsəbəl/ adjective
irrepressible
/ˌirɪˈprɛsəbəl/
adjective
Britannica Dictionary definition of IRREPRESSIBLE
1 
: impossible to hold back, stop, or control
2 
: very lively and cheerful

— irrepressibly

/ˌirɪˈprɛsəbli/ adverb