conspiratorially
🇺🇸
/kənˌspɪrəˈtɔːriəli/
🇬🇧
/kənˌspɪrəˈtɔːriəli/
in a secretive or sneaky way, like someone planning something wrong together
They spoke conspiratorially about their plan to sneak out after dark.
in a way that suggests sharing a secret
She looked around and whispered conspiratorially, 'We have a surprise party planned for him.'