poser
Another word for addition which starts with the letter N is New.
letter
Another word for water that starts with the letter 'O' is oxygen dihydrogen.
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astamp
Atop.
Astonishing.
Amazing
advertise
"Deceiver" is another word for liar that starts with the letter A.
Orator is another word for speaker.
Authority can be used as another word for expert and starts with an "A". Example: An authority on the subject of crime, notes that...