Plain damage I repair (7)
I believe the answer is:
prairie
'plain' is the definition.
(thesaurus)
'damage i repair' is the wordplay.
'damage' indicates an anagram (I've seen this in other clues).
'i'+'repair'='irepair'
'irepair' anagrammed gives 'PRAIRIE'.
(Other definitions for prairie that I've seen before include "this oyster produces an egg" , "Tract of (US) grassland" , "Broad rolling tract of land in the US" , "Extensive US grassland" , "Large tract of grassland in N America" .)