pre·car·i·ous /prɪˈkæriəs, ˈkɛr-/
 (a.)不穩定的,不安的,危險的
 Pre·ca·ri·ous a.
 1. Depending on the will or pleasure of another; held by courtesy; liable to be changed or lost at the pleasure of another; as, precarious privileges.
 2. Held by a doubtful tenure; depending on unknown causes or events; exposed to constant risk; not to be depended on for certainty or stability; uncertain; as, a precarious state of health; precarious fortunes. “Intervals of partial and precarious liberty.”
 Syn: -- Uncertain; unsettled; unsteady; doubtful; dubious; equivocal.
 Usage: -- Precarious, Uncertain. Precarious in stronger than uncertain. Derived originally from the Latin precari, it first signified “granted to entreaty,” and, hence, “wholly dependent on the will of another.” Thus it came to express the highest species of uncertainty, and is applied to such things as depend wholly on future casualties.
 -- Pre*ca*ri*ous*ly, adv. -- Pre*ca*ri*ous*ness, n.
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 precarious
      adj 1: affording no ease or reassurance; "a precarious truce" [syn:
              unstable]
      2: fraught with danger; "dangerous waters"; "a parlous journey
         on stormy seas"; "a perilous voyage across the Atlantic in
         a small boat"; "the precarious life of an undersea diver";
         "dangerous surgery followed by a touch-and-go recovery"
         [syn: parlous, perilous, touch-and-go]
      3: dangerously insecure; "a precarious footing on the ladder"
      4: not secure; beset with difficulties; "a shaky marriage"
         [syn: shaky]