Context: before a boxing match begins, a boxer named Kamishiro says this referring to his opponent:
勘だけど あのカックン野郎… 刺せるヤツだ
What is the meaning of カックン? The opponent was a thug in the past and he his obsessed with precisely cut hair, but none of these details seems to be relevant. The only similar expression I could find is 膝カックン, but I don't think it could fit the context.
Here you can see the page before and the page with the sentence in question. Thank you for your help!