Hi or how do you do (5)
I believe the answer is:
hello
I believe this is a double definition.
'hi' is the first definition.
(synonyms)
'how do you do' is the second definition.
(synonyms)
(Other definitions for hello that I've seen before include "A salutation" , "Conventional word of greeting" , "glossy magazine" , "Greeting - celebrity magazine" , "I say" .)