Is going to Wales; was left land (4)
I believe the answer is:
isle
'land' is the definition.
(isle is a kind of land)
'is going to wales was left' is the wordplay.
'going to' means one lot of letters go next to another.
'left' suggests deleting specific letters (some letters have left).
'wales' with 'was' taken out is 'le'.
'is'+'le'='ISLE'
(Other definitions for isle that I've seen before include "It lies badly in water" , "The Lake ... of Innisfree (W.B.Yeats)" , "9 ac perhaps" , "man with capital?" , "one ringed in the main?" .)