The words vaper, vapor sound the same but have different meanings and spellings. Why do vaper, vapor sound the same even though they are completely different words?
The answer is simple: vaper, vapor are homophones of the English language.
A "<xref>smoker</xref>" of <xref>electronic cigarettes</xref>.
a visible suspension in the air of particles of some substance
the process of becoming a vapor
To use insubstantial language; to <xref>boast</xref> or <xref>bluster</xref>.
To turn into vapor.
Definitions from Wiktionary, Creative Commons Attribution/Share-Alike License., from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved. and Wordnik.
Homophones (literally "same sound") are usually defined as words that share the same pronunciation, regardless of how they are spelled.