Synonyms that are in the dictionary are marked in green. Synonyms that are not in the dictionary are marked in red.
Antonyms that are in the dictionary are marked in green. Antonyms that are not in the dictionary are marked in red.
Since the room becomes available after completing a good chunk of the main quests, it is possible to plant the Mallowsweet in the Herbology Classroom’s Pot temporarily and wait for the Room of Requirement quest to trigger.
Source: https://gamerant.com/hogwarts-legacy-get-mallowsweet-ingredient-merlin-trial/