This
word is often used to show that someone is enthusiastic about something
or someone. You might say that
'Fred
is a keen cricketer, he loves to play cricket every Sunday for his local
team.'
or
'Tracy
is a keen student, she studies every day.'
You
can also say that
'Tony
is rather keen on Susan'
and
that means he is attracted to her!
If you
say that
'There
was keen competition for the singing prize. All of the singers were very
good.'
In
this case 'keen' means intense or strong.