A gentle land (6)
I believe the answer is:
alight
'land' is the definition.
(I know that alight is a type of land)
'a gentle' is the wordplay.
'gentle' becomes 'light' (synonyms).
'a'+'light'='ALIGHT'
(Other definitions for alight that I've seen before include "Disembark, land" , "Descend from vehicle" , "'Step off, a bus, say (6)'" , "Burning; descend" , "Touch down" .)