Calls on head regularly for welcome (5)
I believe the answer is:
aloha
'welcome' is the definition.
(I've seen this before)
'calls on head regularly' is the wordplay.
'regularly' means one should take alternating letters (regularly take one letter, leave next etc.).
'calls'+'on'+'head'='callsonhead'
The alternate letters of 'callsonhead' are 'ALOHA'.
'for' is the link.
(Other definitions for aloha that I've seen before include "A halo seen in Polynesian greeting" , "A greeting in Hawaii" , "A Hawaiian welcome" , "Hawaiian farewell" , "Hello or goodbye in Hawaii" .)