You certainly can! This is highly encouraged, especially when drilling in the Flashcards section.
You can correct your translations in one of three places:
1. While reading - open the sidebar by clicking the ☰ button at the top right of the page, then go to the Words tab and click the appropriate word to see its edit controls.
2. While practicing Flashcards - the first time you encounter a flashcard, after clicking to reveal the translation, click the little pencil icon at the bottom right of the translated side to see the edit controls.
3. While reviewing your Word List- click on the appropriate word to reveal the edit controls.