Simpleton’s lodging-place in US city (5)
I believe the answer is:
ninny
'simpleton's' is the definition.
(ninny is a kind of simpleton)
'lodging-place in us city' is the wordplay.
'lodging-place' becomes 'inn'.
'in' indicates putting letters inside.
'us city' becomes 'ny' (I've seen this in other clues).
'inn' put into 'ny' is 'NINNY'.
(Other definitions for ninny that I've seen before include "Stupid foolish person" , "Simpleton" , "gravely so miscalled by mechanicals" , "not a wise man" , "dope" .)