Hazardous (9)

'hazardous' is the definition.
(similar in meaning)
This is all the clue.
(Other definitions for dangerous that I've seen before include "Harmful, injurious" , "posing a threat" , "Hazardous" , "likely to blow up" , "posing risk" .)
(Other definitions for breakneck that I've seen before include "Dangerously fast" , "rash" , "This speed is recklessly dangerous" , "high speed" .)
'hazardous' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for perilous that I've seen before include "Hazardous, menacing" , "Full of danger" , "Hazardous, dangerous" , "Extremely dangerous" , "promising danger" .)
'hazardous' is the definition.
(I know that hazardous can be written as risky)
This is the entire clue.
(Other definitions for risky that I've seen before include "Hazardous" , "not playing safe" , "Treacherous" , "Chancy" , "too adventurous" .)
'hazardous' is the definition.
(similar in meaning)
This is the entire clue.
(Other definitions for unsafe that I've seen before include "Perilous" , "giving no protection" , "Hazardous" , "Dangerous, insecure" , "Unreliable" .)