Regularly appraised, admitting look's plain (7)
I believe the answer is:
prairie
'plain' is the definition.
(thesaurus)
'regularly appraised admitting look's' is the wordplay.
'regularly' indicates alternate letters (regularly take one letter, leave next etc.).
'admitting' means one lot of letters goes inside another.
'look' becomes 'air' (I've seen this before).
The alternate letters of 'appraised' are 'prie'.
'prie' going around 'air' is 'PRAIRIE'.
(Other definitions for prairie that I've seen before include "Continental grassland of N America" , "Broad rolling tract of land in the US" , "Schooners once crossed it" , "Cowboy song: ` `Bury me not on the lone .......' '" , "Large treeless tract of grassland" .)