Really keen about (4)
I believe the answer is:
into
(Other definitions for into that I've seen before include "Keen on (informal)" , "Curious about" , "Enthusiastic about" , "Keen on, colloquially" , "ignition regularly missing" .)
I believe the answer is:
into
(Other definitions for into that I've seen before include "Keen on (informal)" , "Curious about" , "Enthusiastic about" , "Keen on, colloquially" , "ignition regularly missing" .)