Other forms: undeviatingly
The adjective undeviating means staying on a course or sticking with a plan. If you take the same, undeviating route across a field every day, you'll eventually wear a visible path in the grass.
Another meaning of this word is "steady or constant," like the undeviating love you feel for your pet rabbit or the undeviating attention you pay to an exciting episode of your favorite TV show. To deviate is veer off a path, from the Latin deviare, "turn out of the way," and its root, the phrase de via or "off way."