inscrutable
- Impossible to understand or interpret; not readily giving away feelings, thoughts, or motives.
In a sentence
- The judge's inscrutable expression gave no hint of how he would rule.
- The ancient text remained inscrutable until a bilingual inscription was discovered nearby.
Usage note. Be aware that applying inscrutable to a person from a particular cultural background can carry a stereotyping history; use it carefully and favor describing specific behavior instead.
Where it comes from
English inscrutable · entered English 15th c.
From Late Latin 'inscrutabilis,' meaning 'that cannot be searched into,' composed of 'in-' (not) and 'scrutari,' meaning 'to search or examine carefully' (the same root as 'scrutiny'). It entered English in the 15th century.