However, this rule has exceptions, and "envy" is one of them.
Here's why:
* The rule is meant to be a general guide, not a hard-and-fast rule. There are many words that don't follow it.
* The word "envy" comes from the French word "envie," which has a "y" at the end. The spelling was adopted into English without changing the "y" to "i".
Therefore, while the rule might seem applicable, "envy" is an exception, and the "y" spelling is correct.