Take back park — Liberal’s first intention (7)
I believe the answer is:
reclaim
'take back' is the definition.
(thesaurus)
'park liberal's first intention' is the wordplay.
'park' becomes 'rec' (I've seen this in other clues).
'first' indicates taking the first letters.
'intention' becomes 'aim' ('aim' can be a synonym of 'intention').
The initial letter of 'liberals' is 'l'.
'rec'+'l'+'aim'='RECLAIM'
(Other definitions for reclaim that I've seen before include "Win back" , "Miracle (anag)" , "Recover (materials/land) for subsequent use" , "'Make useful again, land say (7)'" , "Make (land) available for use" .)