1. Literally, to feel thirsty, especially for some beverage in particular (which is named after "for"). On hot days like this, I always seem to have a thirst for lemonade.

2. To have an intense desire, yearning, or need for something. Even from a young age he had a thirst for knowledge, devouring any he could get his hands on. Growing up in such a small, secluded town, I constantly had a thirst for romance and adventure.