- Of or relating to a secret plan or agreement to do something illegal or harmful.
- Of or relating to a secret plan or scheme to achieve a particular goal.
- Relating to or suggestive of conspiracy.
Late 19th century: from conspirator + -ial.
- He had a conspiratorial look in his eye, which made me suspicious.
- The police discovered a conspiratorial note that provided evidence of the plot.
- The conspiratorial whispers among the group raised suspicions among the authorities.
- She had a conspiratorial smile as she shared her secret plan with me.
- The conspiratorial tone in his voice made me think that he was involved in some illegal scheme.