Walking (2,4)
'walking' is the definition.
(synonyms)
This is all the clue.
(Other definitions for on foot that I've seen before include "where the corn's growing?" , "Walking or running" , "Going as pedestrian" , "By shanks's pony" .)
'walking' is the definition.
(hiking is a kind of walking)
This is the entire clue.
(Other definitions for hiking that I've seen before include "on a walk" , "On a trek" , "Raising" , "Rambling" , "Walking in the countryside" .)
'walking' is the definition.
(pacing is a kind of walking)
This is the entire clue.
(Other definitions for pacing that I've seen before include "Walking about, perhaps impatiently" , "Walking about, perhaps frustrated" .)
'walking' is the definition.
(I know that ambulation is a type of walking)
This is all the clue.
(Other definitions for on air that I've seen before include "In the process of broadcasting - floating aloft?" , "Walk in delight here" , "Broadcasting at this moment" , "(Walking) elatedly" , "Broadcasting studio sign" .)