means The activity of taking a long, vigorous walk through the countryside, hills, or mountains, usually for pleasure or exercise.

from From the verb "hike," which surfaced in English dialect around the early 19th century meaning to walk vigorously or tramp about. Its deeper roots are murky — it may be related to "hitch," the idea of moving with a jerk or pulling oneself along, but honestly the connection is uncertain. The word stayed regional and informal for a while before striding into mainstream use, eventually picking up the extra sense of raising something sharply (a "price hike"), as if the cost itself had gone for a brisk uphill walk.