unselfconscious

US /ˌʌn.selfˈkɑːn.ʃəs/
UK /ˌʌn.selfˈkɑːn.ʃəs/
1.

vô thức

not worried about other people's opinions of you, about doing things in a particular way, or about being impressive:

:
He danced with unselfconscious abandon.