Answer: snakier

AnswerCrossword Clue
SNAKIER

More treacherous

SNAKIER

More like a mountain road

SNAKIER

More sinuous

SNAKIER
More winding, as a path
SNAKIER
Slyer.
SNAKIERMore sinuous.
SNAKIERMore treacherous.
SNAKIERMore wriggly.
SNAKIERWith more curves