I regain form of land (7)
I believe the answer is:
nigeria
'land' is the definition.
(Nigeria is an example)
'i regain form' is the wordplay.
'form' indicates anagramming the letters.
'i'+'regain'='iregain'
'iregain' with letters rearranged gives 'NIGERIA'.
'of' is the link.
(Other definitions for nigeria that I've seen before include "former colony" , "African republic, capital Abuja" , "W. African country" , "West African republic" , "Land in Africa" .)