The word you're looking for is "long." When you add the letters "e" and "r" to it, it becomes "longer." This clever play on words highlights how the meaning changes with the addition of letters.
The word is SHORT it was 5 letter you then add ER
"Short" is a five-letter word that becomes shorter when you add two letters.
I'm not sure you got all of it. Riddles of this nature usually take the form of, "What word becomes shorter when you add two letters to it?" The answer is "short." Alternatively, "What seven-letter word becomes longer when you take one letter away?" The answer is "lounger."
short
The word "short", if you add the letters 'e'and 'r'.
short
Small of course !
New Zealand
short
The 5 letter word is short. It becomes shorter when 'er' is added.
short
"What five letter word becomes shorter when you add two letters to it?"short + er = shorter