IPA: /kənˌspɪrəˈtɔːriəl/
KK: /kənˌspɪrəˈtɔriəl/
Relating to or characteristic of secret plans made by a group to do something unlawful or harmful.
He gave her a conspiratorial wink, as if they were sharing a secret.
Conspiratorial → It is formed from "con-" (meaning together) and "spirare" (meaning to breathe). The word refers to the act of breathing together, which metaphorically extends to secretive plotting or scheming together.
Think of people 'together' ('con-') 'breathing' ('spirare') in a secretive manner — that's why conspiratorial relates to secret plots.