Welcome in Idaho lads rejected (5)
I believe the answer is:
aloha
'welcome' is the definition.
(I've seen this before)
'in idaho lads rejected' is the wordplay.
'in' indicates a hidden word.
'rejected' shows that the letters should be reversed in order.
'ahola' can be found hidden inside 'idaho lads'.
'ahola' backwards is 'ALOHA'.
(Other definitions for aloha that I've seen before include "A halo seen in Polynesian greeting" , "16 across in Hawaii" , "Hello from Honolulu?" , "A Hawaiian welcome" , "Hawaiian hello or goodbye" .)