i-adjective
extremely dangerous; full of peril
Emphatic expression meaning 'dangerous in the extreme'. Often used in formal or written contexts to stress the severity of a risk.
この山道は危険極まりないので、夜間の通行は禁止されている。
This mountain path is extremely dangerous, so nighttime passage is prohibited.
彼の無謀な運転は危険極まりない行為
His reckless driving is an act full of peril.
Compound of 危険 (danger) + 極まりない (extremely, exceedingly). The suffix 極まりない attaches to nouns to express 'the ultimate in...' or 'extremely...'.