Moving stair maybe (5)
I believe the answer is:
astir
'moving' is the definition.
(I've seen this before)
'stair maybe' is the wordplay.
'maybe' indicates an anagram.
'stair' anagrammed gives 'ASTIR'.
(Other definitions for astir that I've seen before include "This isn't still" , "In motion - out of bed" , "Out of bed or on the move" , "In a state of movement" , "Moving; out of bed" .)