One way up, perhaps Crossword Clue

 The answer to the crossword clue "One way up, perhaps" is STAIRS.

This is a cryptic clue, which means that the answer is not literally the one-word definition of the clue. Instead, the clue is a pun or other wordplay that hints at the answer. In this case, the word "stairs" can be interpreted as a way to go up, and the word "perhaps" suggests that there may be only one way to go up.

Other possible answers to this clue include:

Ladder

Escalator

Climbing rope

Zip line

Elevator (if there is only one elevator)

The best answer will depend on the specific context of the crossword puzzle.