Devious means getting what you want by underhand means. A devious plan, devious methods, thoroughly devious.
It is always disapproving of people, but the older sense is neutral and geographic: a devious route is simply a roundabout one, off the direct road, which is exactly what the Latin says. The moral sense is the same picture applied to conduct.
1adjectivedeviousGetting what you want by underhand means.
“She came up with a devious plan to get her rival fired without anyone knowing.”
devious is a quality.
Latin devius means off the road — de, away from, plus via, a road. Deviate is the same root.
Latin
devius — out of the way, remote, off the main road
English, today
devious
Built from
1590s, "out of the common or direct way," from Latin devius (“out of the way, remote, off the main road”), from de via, from de#Latin:_preposition (“off”) (see de-) + via (“way, road”). Compare deviate. Originally in the Latin literal sense; the figurative sense of "deceitful" is first recorded 1630s. Related to deviously, deviousness. Figurative senses of the Latin word were "retired, sequestered, wandering in the byways, foolish, inconsistent."
Etymology from Wiktionary, CC BY-SA