Extremely excited about something. So excited there is an inability to think of any other word at the time so the swear word shit is used.
Hey man want to ride my motorcycle?
Oh my god! Hell yes! I’m keen as shit
swift run
Then he tiptoed his way cautiously among the tree till he felt that he was out of hearing, and straightway broke into a keen run in the direction of the sandbar.
I take a keen run when a dog bark at me.
to make something so bad its funny
fred wrote a joke book but his editor keened it
when someone makes a joke/comic/story thats so dumb its funny
fred made joke book but his ghost writer keened it
when you don't have a clue what to say and you need to fill in the silence
when someone tells a really stupid joke but its so dumb its funny
fred really pulled a keen when he told the pun about zebras
He tiptoed his way cautiously among the trees till he felt that he was out of hearing, and straightway broke into a keen run in the direction of the sandbar.