dangerous desultory doubtful dubious fly-by-night hazardous infirm insecure insubstantial irresponsible perilous precarious provisional questionable risky rocky shaky shifting shifty slippery temporary tentative ticklish tottery treacherous trustless unassured uncertain undependable unfaithworthy unhealthy unpredictable unreliable unsafe unsolid unsound unstable unsteadfast unsteady unsubstantial unsure untrusty