dangerous, risky, hazardous, perilous, precarious
in danger, in jeopardy, critical, grave, at risk
uncertain, unreliable, insecure, unsteady, doubtful
close (i.e. a close call), narrow
dangerous; in danger; facing imminent danger
precarious (situation); perilous (state, balance, etc.); in doubt; in jeopardy; uncertain; insecure; concerning; worrying