Walk round Lake District? (5)
I believe the answer is:
place
'district?' is the definition.
(thesaurus)
'walk round lake' is the wordplay.
'walk' becomes 'pace' (pacing is a kind of walking**).
'round' indicates putting letters inside.
'lake' becomes 'l'.
'pace' placed around 'l' is 'PLACE'.
(Other definitions for place that I've seen before include "square?" , "Put in - winning position" , "Site" , "Scene; put" , "Location; put" .)