pre·car·i·ous 
(prĭ-kârē-əs)
(prĭ-kârē-əs)adj.
1. Dangerously lacking in security or stability: a precarious posture; precarious footing on the ladder.
2. Subject to chance or unknown conditions: "His kingdom was still precarious; the Danes far from subdued" (Christopher Brooke).
3. Based on uncertain, unwarranted, or unproved premises: a precarious solution to a difficult problem.
4. Archaic Dependent on the will or favor of another.
[From Latin precārius, obtained by entreaty, uncertain, from precārī, to entreat; see PRAY.]
pre·cari·ous·ly adv.
pre·cari·ous·ness n.