Regularly outstay welcome in country (3)
I believe the answer is:
usa
'welcome in country' is the definition.
'U.S.A.' can be an answer for 'country' (U.S.A. is an example). I'm not certain of the 'welcome in' bit.
'regularly outstay' is the wordplay.
'regularly' means one should take alternating letters (regularly take one letter, leave next etc.).
The alternate letters of 'outstay' are 'USA'.
Can you help me to learn more?
(Other definitions for usa that I've seen before include "Briefly, a great federation" , "Land of the Free and the Home of the Brave" , "Trumpland?" , "11 Nation" , "Union" .)