【Address】 , 【accost】 , 【greet】 , 【salute】 and hail all mean to speak to or less often to write or make a sign to a person in recognition or in order to obtain recognition.
【Address】 usually implies formality and definite purpose; it also frequently suggests length of speech or communication ( 【address】 a petition to Congress) <how does one 【address】 a governor?)
- it was Franklin, the thick chief mate, who was addressing him
—Conrad
【Accost】 adds to 【address】 the idea of speaking first or without being introduced; it implies absence of formality and often suggests boldness or sometimes evil intent <he accosted a passerby and asked for money
- the women . . . were accosted by two men who wanted to walk with them
—Anderson
【Greet】 usually implies friendliness, goodwill, or cordiality; it is the precise word when welcoming is to be suggested.
- the whole town appeared at the station to 【greet】 them
- my lord, the Mayor of London comes to 【greet】 you
—Shak.
【Salute】 commonly stresses ceremoniousness or observance of courtesies demanded by custom.
- the wife of his brother . . . must be saluted every day; but his paternal and maternal kinswomen need only be greeted on his return from a journey
—William Jones - then 1 【salute】 you with this kingly title: long live Richard, England′s royal king
—Shak.
Specifically 【salute】 applies to formal or prescribed acts of recognition.
- the soldier saluted his superior officer
- the president was saluted with 21 guns
Hail implies heartiness, joyousness, and often noisiness.
- he smiled and nodded and saluted to those who hailed him
—MasefieId
It often stresses the idea of calling out especially from a distance
