keen (adj)

They were very keen to start work as soon as possible.
Joan wanted to go to a movie but I wasn't keen (= I didn't want to go).
She's a keen tennis player.
She is keen to learn new languages and cultures.
A keen interest in astronomy led him to pursue a career in astrophysics.
The teacher noticed the students' keen enthusiasm for the science experiment.
A keen sense of observation is essential for scientific research.