One important point here is that "justification" is not the right word for the Persian word "keshidan" (or any other word you prefer for that effect), for several reasons:
1. "justification", being one way to adjust line width in paragraphs, has had good equivalents in Persian for decades, like "faasele-bandi".
2. What we are discussing here is not about line width adjustment, but some effect on word(s). Using the same word for two different methods in two different levels of typesetting/typography -- with similar effects in the word level -- could be confusing for everyone, specially non-natives.
3. The word "justification" implies adjusting something (like line width) to some value (another line width or paragraph width), which is not applicable in this case, which are just "making the word length longer".
In 2004, the only reasonable word I found for the concept was "elongation" -- and "word elongation", to go with "word spacing", "letter spacing", etc.
Anyone has a better suggestion for English word?
-Behnam