pre·car·i·ous /prəˈkerēəs/ adjective not securely held or in position; dangerously likely to fall or collapse. dependent on chance; uncertain. synonyms: uncertain, insecure, unreliable, unsure, unpredictable, undependable, risky, hazardous, dangerous, unsafe, hanging by a thread, hanging in the balance, perilous, treacherous, on a slippery slope, on thin ice, touch-and-go, built on sand, doubtful, dubious, delicate, tricky, problematic; MoreAll Rights Reserved