On the level
Meaning
Honest and straightforward.
Usage
Used when trusting someone's word.
Origin & History
Origins and dates here are approximate summaries. Many idioms have disputed or unknown origins, and not every date has been checked against a historical dictionary, so treat specific dates and stories as a starting point rather than a citation.
Surveyors used level rods to ensure fairness; now refers to sincerity.
19th-century legal language adopted the metaphor.