Greeting with a look and a laugh (5)
I believe the answer is:
aloha
'greeting' is the definition.
(I've seen this in another clue)
'a look and a laugh' is the wordplay.
'a look' becomes 'lo' ('lo' is an archaic exclamation meaning 'look!').
'and' means one lot of letters go next to another.
'laugh' becomes 'ha'.
'lo' put after 'a' is 'alo'.
'alo'+'ha'='ALOHA'
'with' acts as a link.
(Other definitions for aloha that I've seen before include "greeting in Oahu" , "Welcome to Honolulu!" , "A halo seen in Polynesian greeting" , "Hawaiian greeting" , "Hi! in Honolulu" .)