— breakneck
— chanceful
— chancy
— desperate
— dicey
— dodgy
— hazardous
— insidious
— mordacious
— on the hook
— out on a limb
— parlous
— perilous
— precarious
— risky
— self-destructive
— shaky
— suicidal
— touch-and-go
— treacherous
— unacceptable
— unaccepted
— uncivil
— uncivilised
— uncouple
— uncover
— uncovered
— unexpected
— unexpressed
— unguaranteed
— unmixable
— unoccupied
— unprotected
— unreliable
— unsavory
— unsavoury
— unsecured
— unsparing
— unspeakable
— unspecific
— unspecified
— unspoiled
— unspoken
— unusable
— vulnerable
— wild