maître à penser
/ˌmeɪtrə a ˈpɒnseɪ/ /ˌmɛtr a ˈpɒ̃seɪ/noun
An influential thinker in a particular field, especially philosophy or literature.
Origin
1950s; earliest use found in Encounter. From French maître à penser, lit. ‘master of thinking’ from maître master + à to, at, in + penser to think.