unsafe vs breakneck

unsafe and breakneck both are adjectives.

Word	Noun	Adjective	Verb	Adverb
unsafe	No	Yes	No	No
breakneck	No	Yes	No	No

unsafe (adjective)	breakneck (adjective)
involving or causing danger or risk; liable to hurt or harm	moving at very high speed
lacking in security or safety
not safe from attack