Is half a mile away from land (4)
I believe the answer is:
isle
'land' is the definition.
(isle is a kind of land)
'is half a mile' is the wordplay.
'half a' suggests halving the letters.
'mile' with half the letters taken is 'le'.
'is'+'le'='ISLE'
'away from' is the link.
This may not be right. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for isle that I've seen before include "Dogs, maybe" , "Small mass of land in the sea" , "Insular place" , "Of Man or Youth, for example" , "Sea-girt area" .)