Pacific greeting sounds like a deep laugh (5)
I believe the answer is:
aloha
'pacific greeting' is the definition.
(I've seen this in another clue)
'a deep laugh' is the wordplay.
'a deep' becomes 'alo' (I am not sure about this - if you are sure you should believe this answer much more).
'laugh' becomes 'ha'.
'alo'+'ha'='ALOHA'
'sounds like' is the link.
Can you help me to learn more?
(Other definitions for aloha that I've seen before include "Hawaiian greeting" , "greeting in Oahu" , "Hello from Honolulu?" , "A halo seen in Polynesian greeting" , "A greeting in Hawaii" .)