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 all the 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.
(synonyms)
This is all the 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 all the clue.
(Other definitions for unsafe that I've seen before include "Perilous" , "giving no protection" , "Hazardous" , "Dangerous, insecure" , "Unreliable" .)
(Other definitions for chancy that I've seen before include "'Dodgy, dicey (6)'" , "Informally uncertain or risky" .)